Fluorescent maleimides and uses thereof

ABSTRACT

Fluorescent maleimides of the formula I  
                 
 
     wherein  
     R 1  and R 2  independently from each other stand for  
                 
 
     wherein Q 1  stands for hydrogen, halogen, phenyl, —E—C 1 -C 8 alkyl, —E-phenyl, wherein phenyl can be substituted up to three times with C 1 -C 8 alkyl, halogen, C 1 -C 8 alkoxy, diphenylamino, —CH═CH—Q 2 , wherein Q 2  stands for phenyl, pyridyl, or thiophenyl, which can be substituted up to three times with C 1 -C 8 alkyl, halogen, C 1 -C 8 alkoxy, —CN, wherein E stands for oxygen or sulfur, and wherein R 21  stands for C 1 -C 8 alkyl, phenyl, which can be substituted up to three times with C 1 -C 4 alkyl, C 1 -C 4 alkoxy, or dimethylamino, and R 22  and R 23  independently from each other stand for hydrogen, R 21 , C 1 -C 8 alkoxy, or dimethylamino,  
     or —NR 4 R 5 , wherein R 4  and R 5 , independently from each other stand for hydrogen, phenyl, or C 1 -C 8 alkyl-carbonyl, or —NR 4 R 5  stands for a five- or six-membered ring system, and R 3  stands for allyl,  
                 
 
     wherein Q 3  stands for hydrogen, halogen, C 1 -C 8 alkoxy, or C 1 -C 8 alkyl-amido, unsubstituted or substituted C 1 -C 8 alkyl, unsubstituted or up to three times with halogen, —NH 2 , —OH, or C 1 -C 8 alkyl substituted phenyl,  
     and Z stands for a di- or trivalent radical selected from the group consisting of substituted or unsubstituted cyclohexylene, preferably 1,4-cyclohexylene, triazin-2,4,6-triyl, C 1 -C 6 alkylene, 1,5-naphthylene,  
                 
 
     wherein  
     Z 1 , Z 2  and Z 3 , independently from each other stand for cyclohexylene or up to three times with C 1 -C 4 alkyl substituted or unsubstituted phenylene, preferably unsubstituted or substituted 1,4-phenylene,  
     and wherein R 6  and R 7 , independently from each other, stand for  
                 
 
     n stands for 1, 2 or 3, and m stands for 1 or 2, with the proviso, that R 1  and R 2  not simultaneously stand for phenyl,  
     and its different uses such as in electroluminescent devices and as void detection compounds.

[0001] The present invention relates to fluorescent maleimides of theformula I

[0002] wherein

[0003] R₁ and R₂ independently from each other stand for

[0004] wherein Q₁ stands for hydrogen, halogen, phenyl, —E—C₁-C₈alkyl,—E-phenyl, wherein phenyl can be substituted up to three times withC₁-C₈alkyl, halogen, C₁-C₈alkoxy, diphenylamino, —CH═CH—Q₂, wherein Q₂stands for phenyl, pyridyl, or thiophenyl, which can be substituted upto three times with C₁-C₈alkyl, halogen, C₁-C₈alkoxy, —CN, wherein Estands for oxygen or sulfur, and wherein R₂₁ stands for C₁-C₈alkyl,phenyl, which can be substituted up to three times with C₁-C₄alkyl,C₁-C₄alkoxy, or dimethylamino, and R₂₂ and R₂₃ independently from eachother stand for hydrogen, R₂₁, C₁-C₈alkoxy, or dimethylamino,

[0005] or —NR₄R₅, wherein R₄ and R₅, independently from each other standfor hydrogen, phenyl, or C₁-C₈alkyl-carbonyl, or —NR₄R₅ stands for afive- or six-membered ring system, and R₃ stands for allyl,

[0006] wherein Q₃ stands for hydrogen, halogen, C₁-C₈alkoxy,C₁-C₈alkyl-amido, unsubstituted or substituted C₁-C₈alkyl, unsubstitutedor up to three times with halogen, —NH₂, —OH, or C₁-C₈alkyl substitutedphenyl,

[0007] and Z stands for a di- or trivalent radical selected from thegroup consisting of substituted or unsubstituted cyclohexylene,preferably 1,4-cyclohexylene, triazin-2,4,6-triyl, C₁-C₆alkylene,1,5-naphthylene,

[0008] wherein

[0009] Z₁, Z₂ and Z₃, independently from each other stand forcyclohexylene or up to three times with C₁-C₄alkyl substituted orunsubstituted phenylene, preferably unsubstituted or substituted1,4-phenylene,

[0010] and wherein R₆ and R₇, independently from each other, stand for

[0011] n stands for 1, 2 or 3, and m stands for 1 or 2, with theproviso, that R₁ and R₂ not simultaneously stand for phenyl,

[0012] and its different uses such as in electroluminescent devices andas void detection compounds.

[0013] Compounds which are both, fluorescent and photostabile, are rare.This is mainly because fluorescence and photostability are usuallyincompatible with each other. The majority of fluorescent materialsobtained to date are compositions employing fluorescent dyes, showingadvantages of strong fluorescence, however, at the same time poorlightfastness, too. Hence, the known fluorescent materials are appliedfor only limited applications, e.g. interior uses, i.e. almost no usesare known for applications where high lightfastness is required.

[0014] In particular, perylene based compounds (especially compounds ofthe known LUMOGEN® series from BASF) for highly photostabile andfluorescent compounds are used by dissolving it into media such asplastics to give fluorescent compositions. However, their solubility isinsufficient thereby failing in obtaining strong color strength of thecorresponding compositions.

[0015] Further, EP-A 456,609 discloses the preparation and use of abenzoimidazoisoindolone as a highly photostabile and fluorescentpigment. However, this pigment exhibits only a weak solid-statefluorescence and a weak reflection color. In addition, the obtainedcolor range is limited to only greenish yellow to yellow. Anotherdisadvantage is that a kind of benzoimidazoisoindolone irritates theskin and crystal growth is too fast in a polymer matrix.

[0016] Also used are coumarin and rhodamine dyes dispersed in a plasticmatrix (so-called fluorescent pigments). However, their photostabilityis poor.

[0017] Some maleimide derivatives are well-known compounds. E.g.J.Org.Chem. 42 (1977) 2819-2825 describes 1,2-diphenylmaleyl derivativessuch as 1,2-diphenylmaleyl-N-cyclohexylimide as a protecting group foramino functions. Although it is mentioned that these compounds areyellow and fluorescent, no examples and no evaluation is given withregard to fluorescence properties and photostabilities.

[0018] Tetrahedron 51 (1995) 9941-9946 describe the synthesis of themarine alkaloid polycitrin, another red, fluorescent 1,2-diphenylmaleylderivative, and intermediates thereof. However, the object of this workis not to show ways to enhance fluorescent properties and photostabilityof maleimide derivatives.

[0019] U.S. Pat. No. 4,596,867 describes the preparation ofdisubstituted maleic anhydride compounds. On col. 5 it is speculatedthat the imides of this compounds with amines such as t-butylaniline oroctadecylamine can yield soluble compounds useful as fluorescent dyesand markers. However, no examples or other hints are given to supportthis statement. Rather, examples are directed to the preparation ofpolyimides in which the claimed anhydrides are reacted with diamines. Inaddition, there is no teaching of how to increase the photostability offluorescent maleimide compounds.

[0020] Chem. Pharm. Bull. 28(7) (1980) 2178-2184 describes, too,diphenylmaleimides of the formula

[0021] wherein R₈ stands for —CH₂Ph, —CH₂CH₂CH₃, —CH(CH₃)₂, and—CH₂CH(CH₃)₂. Although the compounds are described as yellow fluorescentcompounds nothing is mentioned concerning increasing the properties ofphotostability and fluorescence.

[0022] JP-A2 50123664 describes a method for the preparation of

[0023] wherein R stands for C₁-C₄alkyl, phenyl or tolyl, and Ar standsfor phenyl or tolyl. Explicitly, two compounds are prepared wherein Arstands for phenyl, and R for n-butyl and phenyl, resp. However, nothingis mentioned about fluorescence and photostability. Rather, it isspeculated that this compounds are usable as medical drugs, pesticidesand starting materials thereof.

[0024] Chem. Ber. 26 (1893) 2479 describes the preparation of3,4,3′,4′-tetraphenyl-1,1′ethandiyl-bis-pyrrole-2,5-dione. However,nothing is known with regard to photostability, fluorescence, and itsuses inter alia in electroluminescent devices.

[0025] EP-A 628,588 describes the use of bismaleimides, especially

[0026] to increase the molecular weight of polyamides. However, noteaching is given with regard to the photostability and fluorescence ofthe mentioned compounds and other uses.

[0027] Hence, the object of the present invention was to providephotostabile fluorescent compounds, preferably exhibiting a highphotostability and a strong solid-state and/or molecular statefluorescence. Further, another object is to broaden the range ofavailable colors within this field, preferably strong reflection colors,combined with the abovementioned properties.

[0028] In addition, the provided compounds should be usable inelectroluminescent devices as light-emitting substances, as voiddetection compounds, as inks for security printings, emitters forscintilators, light absorbers for solar collectors, light converters foragriculture etc.

[0029] Especially, fluorescent compounds should be provided which,compared to optical brighteners, have a superior solubility thus makingan incorporation into paints and lacquers more easy. In addition, thefluorescent compounds should show fluorescence in the solid state, asuperior photostability with no or only minimal products leading todiscoloration of e.g. white coatings, a lesser migration, a lessercontamination of the working environment, fluorescence should beobserved only at voids and not at the whole surface yielding a bettercontrast compared to e.g. optical brighteners and allowing the detectionof minor defects or damages. Further, the fluorescent compounds shouldbe useful in dark and white pigmented systems in which opticalbrighteners fail. Finally, fluorescent compounds with a superiorphotostability should be provided allowing long-term void detection,i.e. an inspection after months or maybe years after the application.

[0030] Accordingly, the aforementioned fluorescent maleimides werefound. In addition, novel compounds, their preparation and uses of theprovided compounds such as in electroluminescent devices and as voiddetection compounds were found, too.

[0031] A preferred embodiment of the present invention relates tofluorescent maleimides of the formula II

[0032] wherein R₉ has the meaning of R₁, and R₁₀, stands for R₃.

[0033] Another preferred embodiment of the present invention relates tofluorescent maleimides of the formula III

[0034] wherein R₁₁ stands for R₁, and R₁₂ stands for R₂, wherein R₁₁ andR₁₂ do no stand simultaneously for the same substituent, R₁₃ stands forR₃.

[0035] Another preferred embodiment of the present invention relates tofluorescent maleimides of the formula IV

[0036] wherein R₁₃, R₁₄, R₁₆ and R₁₇ independently from each other standfor the radicals as defined under R₁, and R₁₅ stands for a single bond,or a divalent radical, preferably selected from the group consisting ofsubstituted or unsubstituted cyclohexylen, preferably 1,4-cyclohexylene,C₁-C₄alkylene, 1,5-naphthylene,

[0037] particularly preferred R₁₅ stands for a single bond,2,5-di-tert.-butyl-1,4-phenylene, 1,2-ethylene, 1,5-naphthylene,2,5-dimethyl-1,4-phenylene, 4,5-dimethyl-1,4-phenylene,trans-1,4-cyclohexylene,

[0038] Particularly preferred inventive compounds are the followingcompounds:

[0039] C₁-C₈alkyl is typically linear or branched—where possible—methyl,ethyl, n-propyl, isopropyl, n-butyl, sec.-butyl, isobutyl, tert.-butyl,n-pentyl, 2-pentyl, 3-pentyl, 2,2-dimethylpropyl, n-hexyl, n-heptyl,n-octyl, 1,1,3,3-tetramethylbutyl and 2-ethylhexyl, more preferablyC₁-C₄alkyl such as typically methyl, ethyl, n-propyl, isopropyl,n-butyl, sec.-butyl, isobutyl, tert.-butyl.

[0040] C₁-C₆alkylene is typically methylene, 1,1-, 1,2-ethylene,1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene.

[0041] C₁-C₈alkoxy is typically methoxy, ethoxy, n-propoxy, isopropoxy,n-butoxy, sec.-butoxy, isobutoxy, tert.-butoxy, n-pentoxy, 2-pentoxy,3-pentoxy, 2,2-dimethylpropoxy, n-hexoxy, n-heptoxy, n-octoxy,1,1,3,3-tetramethylbutoxy and 2-ethylhexoxy, preferably C₁-C₄alkoxy suchas typically methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy,sec.-butoxy, isobutoxy, tert.-butoxy.

[0042] Halogen stands for fluoro, chloro, bromo or iodo, preferably forchloro or bromo.

[0043] C₁-C₈alkyl-carbonyl is typically methyl-carbonyl (=acetyl),ethyl-carbonyl, n-propyl-carbonyl, isopropyl-carbonyl, n-butyl-carbonyl,sec.-butyl-carbonyl, isobutyl-carbonyl, tert.-butyl-carbonyl,n-pentyl-carbonyl, 2-pentyl-carbonyl, 3-pentyl-carbonyl,2,2-dimethylpropyl-carbonyl, n-hexyl-carbonyl, n-heptyl-carbonyl,n-octyl-carbonyl, 1,1,3,3-tetramethylbutyl-carbonyl and2-ethylhexyl-carbonyl, more preferably C₁-C₄alkyl-carbonyl such astypically methyl-carbonyl, ethyl-carbonyl, n-propyl-carbonyl,isopropyl-carbonyl, n-butyl-carbonyl, sec.-butyl-carbonyl,isobutyl-carbonyl, tert.-butyl-carbonyl.

[0044] C₁-C₈alkyl-amido is typically acetamido, ethaneamido,n-propaneamido, isopropaneamido, n-butane-amido, sec.-butane-amido,isobutane-amido, tert.-butane-amido, n-pentane-amido, 2-pentane-amido,3-pentane-amido, 2,2-dimethylpropane-amido, n-hexane-amido,n-heptane-amido, n-octane-amido, 1,1,3,3-tetramethylbutane-amido and2-ethylhexane-amido, more preferably C₁-C₄alkane-amido such as typicallyacetamido, ethaneamido, n-propaneamido, isopropaneamido, n-butaneamido,sec.-butaneamido, isobutaneamido, tert.-butaneamido.

[0045] If —NR₄R₅ stand for a five- or six-membered ring system, thefollowing ring systems are preferred: 4-morpholinyl (=morpholino),1-indolinyl, 1- or 2-piperidyl, 1-piperazinyl, 1-indolinyl,2-isoindolinyl, 1-quinuclidinyl, 1-pyrrolidinyl, and 9-carbazolyl.

[0046] The inventive maleyl derivatives I to IV can be synthesizedstarting from the corresponding maleic anhydrides and amines in analogyto methods well known in the art such as described in TetrahedronLetters 31(36) (1990) 5201-5204, J.Org.Chem. 42 (17) (1977) 2819-2825,Chem. Pharm. Bull. 28(7) (1980) 2178-2184, or by methods described inTetrahedron 51(36) (1995) 9941-9946 or JP-A2 50123664.

[0047] In a preferred embodiment the corresponding diarylmaleicanhydride of the formula V

[0048] wherein R₁₈ and R₁₉, independently from each other stand for R₁or R₂, is reacted with an amine H₂N—R₃ or diamine H₂N—Z—NH₂.

[0049] The corresponding maleic anhydrides are known or can be preparedin analogy to known methods e.g. as described in J.Org.Chem. 55 (1990)5165-5170 or U.S. Pat. No. 4,596,867, or as described in detail below.Amines H₂N—R₃ and diamines H₂N—Z—NH₂ are also known and commerciallyavailable from chemical suppliers.

[0050] Usually the molar ratio of anhydride V to amine H₂N—R₃ is chosenin the range of from 0.1:1 to 2:1. Usually the molar ratio of anhydrideV to diamine H₂N—Z—NH₂ is chosen in the range of from 0.5:1 to 5:1.Preferably, the reaction is carried out in the presence of a solvent,wherein the amount of solvent usually is chosen in the range of from 5to 50 weight-%, related to the diarylmaleic anhydride V.

[0051] As solvents usual organic solvents such as acetic acid, toluene,dimethylformamide or a mixture thereof can be chosen.

[0052] The reaction temperature preferably is chosen in the range offrom 80 to 150, more preferred from 100 to 120° C.

[0053] The reaction time—usually depending from the chosen reactiontemperature—preferably is chosen in the range of from 2 to 20 hours.

[0054] After removal of the solvent, the product can be purified byknown methods if desired, e.g. by chromatography, or crystallization.

[0055] If so-called unsymmetrical maleimides I or IV are desired, i.e.R₃ stands for e.g.

[0056] wherein R₆ and R₇ stand for a substituent as described for R₁ andR₂, but are different from the chosen R₁ and R₂, or in formula IV R₁₃and R₁₄ are different from R₁₆ and R₁₇, then it is preferred to addsmall amounts of anhydride V to a surplus of diamine H₂N—Z—NH₂, isolatethe obtained product Va

[0057] and react this amine Va with another anhydride V, in which thearyl substituents, e.g. R₆ and R₇ or R₁₆ or R₁₇, are chosen differentlyfrom R₁₈ and R₁₉. Of course other possibilities shall not be excluded,e.g. if one amino group of the diamine is protected etc.

[0058] Another preferred embodiment relates to a process for thepreparation of maleimides I, wherein in a first step the diarylmaleicanhydride V is reacted with ammonium acetate to yield the intermediateVb

[0059] Intermediate Vb then is reacted with a base, and the obtainedanion in a subsequent step with a halogen compound X—R₃ or X—Z—X toyield a desired product according to formula I.

[0060] Usually, the molar ratio of diarylmaleic anhydride V to ammoniumacetate is chosen in the range of from 0.01:1 to 0.5:1, preferably from0.05:1 to 0.15:1.

[0061] Preferably, the reaction temperature is chosen in the range offrom 80 to 130° C., more preferably under reflux conditions of thereaction mixture. It is preferred, too, to carry out the reaction in asolvent. The amount of solvent preferably is chosen in the range of from10 to 100 weight-%, related to the amount of diarylmaleic anhydride V.

[0062] As solvent usual organic solvents such as toluene, DMF, or amixture thereof, or acetic acid, preferably acetic acid can be used.

[0063] Generally, the reaction time is chosen in the range of from threeto 20 hours.

[0064] The desired intermediate Vb can be worked up in usual ways suchas filtering, washing, and—if desired—further purification bychromatography.

[0065] The molar ratio of the base and intermediate Vb preferably ischosen in the range of from 1:1 to 5:1.

[0066] As a base an alkali metal alkoxide, an alkali metal hydride suchas potassium tert.-butoxide, sodium hydride or potassium hydride,preferably sodium hydride, can be used.

[0067] Preferably, the reaction with the base is carried out in thepresence of a solvent. The amount of solvent can be chosen in the rangeof from 5 to 100 weight-%, related to intermediate Vb. As solvent usualorganic solvents such as N-methylpyrrolidone (“NMP”), or dimethylformamide (“DMF”), preferably DMF, can be used. The reaction temperatureusually is chosen in the range of from 20 to 80° C., preferably roomtemperature.

[0068] The reaction time usually is chosen in the range of from 0.5 to 5hours.

[0069] Preferably, the reaction mixture is not worked up.

[0070] Then, halogen compound X—R₃ or X—Z—X is added to the obtainedreaction mixture. Usually, the molar ratio of X—R₃ or X—Z—X tointermediate Vb is chosen in the range of from 1:1 to 10:1.

[0071] The reaction temperature usually is chosen in the range of from20 to 120° C., preferably room temperature.

[0072] The reaction time usually is chosen in the range of from 0.5 to10 hours.

[0073] After adding water to the reaction mixture, usually 0.5 to 10times in volume related to the amount of solvent, if desired, theobtained diarylmaleimide can be worked up in usual ways such asextraction and/or chromatography.

[0074] Another preferred embodiment relates to a process for thepreparation of diarylmaleic anhydrides V in which a glyoxylic acidderivative VI

[0075] is treated with a base and, subsequently, the thus obtained saltVIa is reacted with a carboxylic acid VII

[0076] wherein (a) R₁₈ stands for R₁ and R₁₉ for R₁ or R₂, or (b) R₁₈stands for R₂ and R₁₉ for R₁.

[0077] Usually, the molar ratio of the base to glyoxylic acid derivativeVI is chosen in the range of from 1:1 to 20:1, preferably from 1.5:1 to3:1.

[0078] As a rule, the temperature during the formation of the salt VIais chosen in the range of from 50 to 110, preferably from 70 to 80° C.

[0079] Preferably, the salt-formation of VIa is carried out in thepresence of an aliphatic alcohol such as C₁-C₄alkanols such as methanol,ethanol, n-, i-propanol, n-, iso-, sek.-, tert.-butanol. The amount ofsolvent usually is chosen in the range of from 3 to 100, based on theamount of glyoxylic acid derivative VI.

[0080] As a base preferably alkoxides such as alkali metal alkoxides,more preferably alkali metal salts of C₁-C₄alkanols such as sodiummethanoate, potassium methanoate, sodium acetate, potassium acetate,sodium n-propanoate, potassium n-propanoate, sodium n-, iso-, sek.-,tert. butanoate, potassium n-, iso-, sek.-, tert.-butanoate, preferablypotassium tert.-butanoate, can be used.

[0081] Usually, the reaction time is chosen in the range of from 0.5 to5 hours.

[0082] As a rule, the obtained salt VIa is separated from the reactionmixture, preferably followed by removal of the solvent and drying overin an atmosphere under reduced pressure.

[0083] In the second step of the above process the salt VIa is mixedwith the carboxylic acid VII usually in the presence of acetic anhydrideat a temperature in the range of from 80 to 140° C., preferably underreflux conditions of the reaction mixture.

[0084] In general, the molar ratio of glyoxylic acid salt derivative VIato carboxylic acid VII is chosen preferably in the range of from 5:1 to0.2:1, preferably from 0.8:1 to 1.2:1.

[0085] Generally, the amount of acetic anhydride to the amount ofglyoxylic acid salt derivative VIa is chosen preferably in the range offrom 0.05:1 to 1:1, preferably from 0.1:1 to 0.2:1.

[0086] Usually, the reaction time of this second step is chosen in therange of from 0.5 to 10, preferably from one to three hours. Theisolation of the product can be carried out by known methods in the art,e.g. removing of acetic anhydride by distillation, preferably under anatmosphere of reduced pressure, followed by washing the product withappropriate organic solvents such as acetone or ethyl acetate or bycrystallization or chromatography etc.

[0087] The carboxylic acid VII can be obtained by reducing the glyoxylicacid derivative VI with a reducing agent such as hydrazine under basicconditions.

[0088] In a preferred embodiment the glyoxylic acid derivative VI istreated with hydrazine or hydrazine monohydrate in a temperature rangeof from 70 to 120° C., preferably under reflux conditions, usually for0.2 to 2 hours. Thereafter, a base such as a alkali metal or earthalkaline metal hydroxide such as sodium hydroxide or potassium hydroxideis added to the reaction mixture after cooling down to a temperature inthe range of from 80 to 100, preferably from 95 to 100° C., and thenheated to a temperature range of from 100 to 120° C., preferably underreflux conditions for 2 to 10 hours. Afterwards, the hydrazine isremoved e.g. by distillation, and the thus obtained reaction mixturepreferably is acidified with a mineral acid such as hydrochloric acid,sulfuric acid, nitric acid, preferably hydrochloric acid, to a pH in therange of from 2 to 4. After that the product can be isolated e.g. byextraction with an appropriate solvent such as methylene chloride,followed e.g. by crystallization or column chromatography.

[0089] The molar ratio of hydrazine to glyoxylic acid derivative VIusually is chosen in the range of from 2:1 to 20:1, preferably from 5:1to 10:1.

[0090] The amount of the base usually is chosen in the range of from 2to 10, preferably from 3 to 5 weight-%, related to glyoxylic acidderivative VI.

[0091] The glyoxylic acid derivative VI can be obtained bysaponification of ester VIII

[0092] wherein R₂₀ stands for C₁-C₄alkyl, in analogy to known methods.

[0093] Preferably, ester VIII is treated with a base such as an alkalimetal hydroxide, preferably sodium hydroxide, potassium hydroxide, andthe like in the presence of a polar solvent such as an C₁-C₄alkanol oran aqueous solution thereof. In a preferred embodiment thesaponification is carried out in the presence of a mixture of water andan alkanol R₂₀OH in a volume ratio of 5:1 to 0.5:1. Further it ispreferred to carry out the saponification at an elevated temperature,such as in the range of from 70 to 100° C., preferably under refluxconditions at ambient pressure.

[0094] The reaction time mainly depends on the reactivity of the eductsand the chosen temperature. E.g. under reflux conditions the reactiontime usually is chosen in the range of from one five hours. After that,the reaction mixture usually is acidified with an acid to a pH range offrom 2 to 4. As an acid mineral acids such as hydrochloric acid,sulfuric acid and nitric acid, preferably hydrochloric acid, can beused.

[0095] Generally, the desired glyoxylic acid derivative VII is isolatedfrom the reaction mixture by known methods such as extraction,crystallization, chromatography, preferably extraction.

[0096] The starting material, ester VIIl, can be prepared by treatingthe aryl compound

R₁₈—H  IX

[0097] with the halogen glyoxylate X

[0098] wherein X stands for a halogen, preferably for chlorine orbromine, in the presence of AIX₃ and a solvent.

[0099] In a preferred embodiment, a mixture of AIX₃ in a solvent such asmethylene chloride is added portionwise, preferably dropwise, to amixture of compounds IX and X.

[0100] Usually, the molar ratio of aryl compound IX to halogenglyoxylate X is chosen in the range of from 0.5:1 to 5:1, preferablyfrom 0.8:1 to 2:1.

[0101] The amount of AIX₃ preferably is chosen in the range of from 1 to2 weight-%, related to the amount of glyoxylate X.

[0102] During the addition of AIX₃ to the mixture of compound IX andglyoxylate X, the reaction temperature is chosen preferably in the rangeof from −10 to 20, more preferably from 0 to 5° C. After the additionthe reaction temperature usually is chosen in the range of from 10 to40° C., the preferred temperature is room temperature.

[0103] The reaction time generally is in the range of from 3 to 20hours.

[0104] Thereafter, the reaction mixture preferably is treated withwater, preferably ice and acidified to a pH in the range of from 2 to 4with one of the above mentioned mineral acids, preferably dilutedhydrochloric acid. The isolation of he product can be carried out withmethods well known in the art such as extraction with dichloromethane ordiethylether. If desired the ester II can be further purified e.g. bychromatography.

[0105] Other compounds such as the intermediate

[0106] can be prepared in analogy to the abovementioned process.

[0107] Another embodiment of the present invention relates to the use ofthe claimed maleimides as well for all other fluorescent maleimidesaccording to the general formula given in this application or mentionedin the examples for scintillator films for the detection of atomic andnuclear radiation. In their simplest form these detectors usuallyconsist of a polymer matrix, such as polystyrene, containing lowconcentrations of a fluorescent maleimide as fluorophore or an energydonor/acceptor mixture containing a fluorescent maleimide as a keycomponent.

[0108] Another embodiment of the present invention relates to the use ofthe claimed fluorescent maleimides or those known compounds mentionedadditionally in the examples for the preparation and use of luminescentsolar energy collectors. The operation of a luminescent solarconcentrator usually is based on the absorption of solar radiation in acollector containing a fluorescent species in which the emission bandshave little or no overlap with the absorption bands. Generally, thefluorescence emission is trapped by total internal reflection andconcentrated at the edges of a collector, which is usually a thin flatplate, to the edge of which a p-n junction photovoltaic ribbon is fixedand the light energy converted to electrical energy. Luminescent solarcollectors usually can collect both direct and diffuse light, and thereis a good heat dissipation of non-utilized energy. Tracking of the sunusually is unnecessary and fluorescent species can be selected to allowmatching if the concentrated light to the maximum sensitivity of thephotovoltaic cell.

[0109] A further embodiment of this invention relates to the use of theclaimed fluorescent maleimides or those known compounds mentionedadditionally in the examples for the preparation and use of printinginks such as gravure, flexo and off-set inks preferably for publication,packagings and laminations, as well as non-impact printings such as inkjet printing inks and electrophotographic toners for printers and copymachines. The maleimides can be applied in the usual method known in theart. The inks can be used also in a way known in the art for functionalinks as well as for security printings for banknotes and indicators.

[0110] Another embodiment of the present invention is related to amethod of coloring high molecular organic materials (having a molecularweight usually in the range of from 10³ to 10⁷ g/mol) by incorporatingthe inventive fluorescent compounds by known methods in the art.

[0111] As high molecular weight organic materials the following can beused such as biopolymers, and plastic materials, including fibres.

[0112] The present invention relates preferably to the use of theinventive maleimides I for the preparation of

[0113] inks, for printing inks in printing processes, for flexographicprinting, screen printing, packaging printing, security ink printing,intaglio printing or offset printing, for pre-press stages and fortextile printing, for office, home applications or graphicsapplications, such as for paper goods, for example, for ballpoint pens,felt tips, fiber tips, card, wood, (wood) stains, metal, inking pads orinks for impact printing processes (with impact-pressure ink ribbons),for the preparation of

[0114] colorants, for coating materials, for industrial or commercialuse, for textile decoration and industrial marking, for roller coatingsor powder coatings or for automotive finishes, for high-solids(low-solvent), water-containing or metallic coating materials or forpigmented formulations for aqueous paints, for the preparation of

[0115] pigmented plastics for coatings, fibers, platters or moldcarriers, for the preparation of

[0116] non-impact-printing material for digital printing, for thethermal wax transfer printing process, the ink jet printing process orfor the thermal transfer printing process, and also for the preparationof

[0117] color filters, especially for visible light in the range from 400to 700 nm, for liquid-crystal displays (LCDs) or charge combined devices(CCDs) or for the preparation of

[0118] cosmetics or for the preparation of

[0119] polymeric ink particles, toners, dry copy toners liquid copytoners, or electrophotographic toners, and electroluminescent devices.

[0120] Illustrative examples of suitable organic materials of highmolecular weight which can be colored with the inventive fluorescentmaleimides of this invention are vinyl polymers, for examplepolystyrene, poly-a-methylstyrene, poly-p-methylstyrene,poly-p-hydroxystyrene, poly-p-hydroxyphenylstyrene, polymethylmethacrylate and polyacrylamide as well as the corresponding methacryliccompounds, polymethylmaleate, polyacrylonitrile, polymethacrylonitrile,polyvinyl chloride, polyvinyl fluoride, polyvinylidene chloride,polyvinylidene fluoride, polyvinyl acetate, polymethyl vinyl ether andpolybutyl vinyl ether; polymers which are derived from maleinimideand/or maleic anhydride, such as copolymers of maleic anhydride withstyrene; polyvinyl pyrrolidone; ABS; ASA; polyamides; polyimides;polyamidimides; polysulfones; polyether sulfones; polyphenylene oxides;polyurethanes; polyureas; polycarbonates; polyarylenes; polyarylenesulfides; polyepoxides; polyolefins such as polyethylene andpolypropylene; polyalkadienes; biopolymers and the derivatives thereofe.g. cellulose, cellulose ethers and esters such as ethylcellulose,nitrocellulose, cellulose acetate and cellulose butyrate, starch,chitin, chitosan, gelatin, zein; natural resins; synthetic resins suchas alkyd resins, acrylic resins, phenolic resins, epoxide resins,aminoformaldehyde resins such as urea/formaldehyde resins andmelamine/formaldehyde resin; vulcanized rubber; casein; silicone andsilicone resins; rubber, chlorinated rubber; and also polymers which areused, for example, as binders in paint systems, such as novolaks whichare derived from C₁-C₆-aldehydes such as formaldehyde and acetaldehydeand a binuclear or mononuclear, preferably mononuclear, phenol which, ifdesired, is substituted by one or two C₁-C₉alkyl groups, one or twohalogen atoms or one phenyl ring, such as o-, m- or p-cresol, xylene,p-tert.-butylphenol, o-, m- or p-nonylphenol, p-chlorophenol orp-phenylphenol, or a compound having more than one phenolic group suchas resorcinol, bis(4-hydroxyphenyl)methane or2,2-bis(4-hydroxyphenyl)propane; as well as suitable mixtures of saidmaterials.

[0121] Particularly preferred high molecular weight organic materials,in particular for the preparation of a paint system, a printing ink orink, are, for example, cellulose ethers and esters, e.g. ethylcellulose,nitrocellulose, cellulose acetate and cellulose butyrate, natural resinsor synthetic resins (polymerization or condensation resins) such asaminoplasts, in particular urea/formaldehyde and melamine/formaldehyderesins, alkyd resins, phenolic plastics, polycarbonates, polyolefins,polystyrene, polyvinyl chloride, polyamides, polyurethanes, polyester,ABS, ASA, polyphenylene oxides, vulcanized rubber, casein, silicone andsilicone resins as well as their possible mixtures with one another.

[0122] It is also possible to use high molecular weight organicmaterials in dissolved form as film formers, for example boiled linseedoil, nitrocellulose, alkyd resins, phenolic resins,melamine/formaldehyde and urea/formaldehyde resins as well as acrylicresins.

[0123] Said high molecular weight organic materials may be obtainedsingly or in admixture, for example in the form of granules, plasticmaterials, melts or in the form of solutions, in particular for thepreparation of spinning solutions, paint systems, coating materials,inks or printing inks.

[0124] In a particularly preferred embodiment of this invention, theinventive fluorescent maleimides I are used for the mass coloration ofpolyvinyl chloride, polyamides and, especially, polyolefins such aspolyethylene and polypropylene as well as for the preparation of paintsystems, including powder coatings, inks, printing inks, color filtersand coating colors.

[0125] Illustrative examples of preferred binders for paint systems arealkyd/melamine resin paints, acryl/melamine resin paints, celluloseacetate/cellulose butyrate paints and two-pack system lacquers based onacrylic resins which are crosslinkable with polyisocyanate.

[0126] According to observations made to date, the inventive fluorescentmaleimides I can be added in any desired amount to the material to becolored, depending on the end use requirements. In the case of highmolecular weight organic materials, for example, the fluorescentmaleimides I prepared according to this invention can be used in anamount in the range from 0.01 to 40, preferably from 0.01 to 5% byweight, based on the total weight of the colored high molecular weightorganic material.

[0127] For the preparation of paints systems, coating materials, colorfilters, inks and printing inks, the corresponding high molecular weightorganic materials, such as binders, synthetic resin dispersions etc. andthe inventive fluorescent maleimides I are usually dispersed ordissolved together, if desired together with customary additives such asdispersants, fillers, paint auxiliaries, siccatives, plasticizers and/oradditional pigments or pigment precursors, in a common solvent ormixture of solvents. This can be achieved by dispersing or dissolvingthe individual components by themselves, or also several componentstogether, and only then bringing all components together, or by addingeverything together at once.

[0128] Hence, a further embodiment of the present invention relates to amethod of using the inventive fluorescent maleimides I for thepreparation of dispersions and the corresponding dispersions, and paintsystems, coating materials, color filters, inks and printing inkscomprising the inventive fluorescent maleimides I.

[0129] A particular embodiment of this invention concerns ink jet inkscomprising the inventive fluorescent compositions.

[0130] The desired ink may contain up to 30% by weight of thefluorescent composition, but will generally be in the range of 0.1 to10, preferably from 0.1 to 8% by weight of the total ink composition formost thermal ink jet printing applications.

[0131] Further, the inks usually contain polymeric dispersants such asrandom, block, branched or graft polymers or copolymers. Most preferredare polymeric dispersants made by the group transfer polymerizationprocess, because in general these are free from higher molecular weightspecies that tend to plug pen nozzles.

[0132] Representative compounds useful for this purpose include e.g.polymers of polyvinyl alcohol, cellulosics and ethylene oxide modifiedpolymers, and dispersant compounds containing ionisable groups such asacrylic acid, maleic acid or sulfonic acid.

[0133] The polymeric dispersant is generally present in an amount in therange of from 0.1 to 30, preferably from 0,1 to 8% by weight of thetotal ink composition.

[0134] In addition to, or in place of the preferred polymericdispersants, surfactants may be used as dispersants. These may beanionic, nonionic, or amphoteric surfactants. A detailed list ofnon-polymeric as well as some polymeric dispersants is disclosed in thesection on dispersants of Manufacturing Confection Publishing Co.,(1990) p. 110-129, McCutcheon's Functional Materials, North AmericaEdition.

[0135] Usually the ink contains an aqueous medium such as water or amixture of water and at least one water-soluble organic solvent.Water-soluble organic solvents are well known, representative examplesof which are disclosed in e.g. U.S. Pat. No. 5,085,698. Selection of asuitable mixture of water and water-soluble organic solvent depends onusually requirements of the specific application such as desired surfacetension and viscosity, drying time of the ink, and the media substrateonto which the ink will be printed.

[0136] Particularly preferred is a mixture of a water-soluble solventhaving at least two hydroxyl groups, e.g. diethylene glycol, and water,especially deionized water.

[0137] In the event that a mixture of water and a water-soluble organicsolvent is used as aqueous medium, water usually would comprise from 30to 95, preferably 60 to 95% by weight, based on the total weight of theaqueous medium.

[0138] The amount of aqueous medium generally is in the range of from 70to 99.8, preferably from 84 to 99.8%, based on the total weight of theink.

[0139] The ink may contain other ingredients well known to those skilledin the art such as surfactants to alter surface tension as well as tomaximize penetration. However, because surfactants may destabilizedispersions, care should be taken to insure compatibility of thesurfactant with the other ink components. In general, in aqueous inks,the surfactants may be present in amounts ranging from 0.01 to 5,preferably from 0.2 to 3% by weight, based on the total weight of theink.

[0140] Biocides may be used in the ink compositions to inhibit growth ofmicroorganisms. Sequestering agents such as EDTA may also be included toeliminate deleterious effects of heavy metal impurities. Other knownadditives, such as viscosity modifiers may also be added.

[0141] A further embodiment concerns the use of the inventivefluorescent compounds I in phase change ink jet inks. The preparation ofsuch inks is well known in the art, e.g. described in detail in EP-A816, 410.

[0142] For the pigmentation of high molecular weight organic material,the inventive maleimides I, optionally in the form of masterbatches,usually are mixed with the high molecular weight organic materials usingroll mills, mixing apparatus or grinding apparatus. Generally, thepigmented material is subsequently brought into the desired final formby conventional processes, such as calandering, compression molding,extrusion, spreading, casting or injection molding. In order to preparenon-rigid moldings or to reduce their brittleness it is often desired toincorporate so-called plasticizers into the high molecular weightorganic materials prior to forming. Examples of compounds which can beused as such plasticizers are esters of phosphoric acid, phthalic acidor sebacic acid. The plasticizers can be added before or after theincorporation of the inventive maleimides I into the polymers. It isalso possible, in order to achieve different hues, to add fillers orother coloring constituents such as white, color or black pigments indesired amounts to the high molecular weight organic materials inaddition to the inventive maleimides I.

[0143] For pigmenting lacquers, coating materials and printing inks thehigh molecular weight organic materials and the inventive maleimides I,alone or together with additives, such as fillers, other pigments,siccatives or plasticizers, are generally dissolved or dispersed in acommon organic solvent or solvent mixture. In this case it is possibleto adopt a procedure whereby the individual components are dispersed ordissolved individually or else two or more are dispersed or dissolvedtogether and only then are all of the components combined.

[0144] The present invention additionally relates to inks comprising acoloristically effective amount of the pigment dispersion of theinventive maleimides I.

[0145] Processes for producing inks especially for ink jet printing aregenerally known and are described for example in U.S. Pat. No.5,106,412.

[0146] The inks can be prepared, for example, by mixing the pigmentdispersions comprising the inventive maleimides I with polymericdispersants.

[0147] The mixing of the pigment dispersions with the polymericdispersant takes place preferably in accordance with generally knownmethods of mixing, such as stirring or mechanical mixing; it ispreferably advisable to use intensive mechanical mixers such as theso-called ULTRATURAX® stirrer from Kunkel & Jahn, Staufen (Germany).

[0148] When mixing a maleimide I with polymeric dispersants it ispreferred to use a water-dilutable organic solvent.

[0149] The weight ratio of the pigment dispersion to the ink in generalis chosen in the range of from 0.001 to 75% by weight, preferably from0.01 to 50% by weight, based on the overall weight of the ink.

[0150] Examples of suitable polymeric dispersants arecarboxyl-containing polyacrylic resins such as polymeric methacrylic orcrotonic acids, especially those obtained by addition polymerization ofacrylic acid or acrylic acid and other acrylic monomers such asacrylates. Depending on the field of use or when using maleimides I, itis also possible, if desired, to admix a small proportion of awater-miscible organic solvent in from 0.01 to 30% by weight, based onthe overall weight of the ink, and/or to admix water and/or bases so asto give a pH in the range from 7 to 11. It may likewise be advantageousto add preservatives, antifoams, surfactants, light stabilizers and pHregulators, for example, to the ink of the invention, depending on thefield of use.

[0151] Examples of suitable pH regulators are inorganic salts such aslithium hydroxide or lithium carbonate, quaternary ammonium hydroxide orammonium carbonate. Examples of preservatives and antifoams are, forexample, sodium dehydroacetate, 2,2-dimethyl-6-acetoxydioxane orammonium thioglycolate. It is also possible to employ known agents whichregulate the viscosity or the surface tension and are described in e.g.U.S. Pat. No. 5,085,698.

[0152] Examples of water-miscible organic solvents are aliphaticC₁-C₄alcohols, such as methanol, ethanol, n-propanol, isopropanol,n-butanol, tert.-butanol, ketones such as acetone methyl ethyl ketone,methyl isobutyl ketone or diacetone alcohol, and also polyols,Cellosolves® and carbitols, such as ethylene glycol, diethylene glycol,triethylene glycol, glycerol, propylene gylcol, ethylene glycolmonomethyl or monoethyl ether, propylene glycol methyl ether,dipropylene glycol methyl ether, tripropylene glycol methyl ether,ethylene glycol phenyl ether, propylene glycol phenyl ether, diethyleneglycol monomethyl or monoethyl ether, diethylene glycol monobutyl ether,triethylene glycol monomethyl or monoethyl ether, and alsoN-methyl-2-pyrrolidone, 2-pyrrolidone, N,N′-dimethylformamide orN,N′-dimethylacetamide.

[0153] If desired, the ink prepared as described above can be worked upfurther. The working up of the ink can be carried out by the customarymethods for working up dispersions, by separation techniques, such assieving or centrifuging the coarse particles from the resultingdispersion. It has been found advantageous, too, to carry outcentrifuging in two stages of different intensity, e.g. centrifuging ina first step for from ten minutes to one hour at from 2000 to 4000 rpmand then, in a second step, for from 10 minutes to one hour at from 6000to 10000 rpm

[0154] Following centrifuging or sieving, the dispersion usually can beused directly as an ink for ink jet printing, for example.

[0155] The present invention additionally relates to a process forproducing color filters comprising a transparent substrate and appliedthereon a red, blue and green layer in any desired sequence, by using ared compound I and known blue and green compounds. The different coloredlayers preferably exhibit patterns such that over at least 5% of theirrespective surface they do not overlap and with very particularpreference do not overlap at all.

[0156] The preparation and use of color filters or color-pigmented highmolecular weight organic materials are well-known in the art anddescribed e.g. in Displays 14/2, 1151 (1993), EP-A 784085, or GB-A2,310,072.

[0157] The color filters can be coated for example using inks,especially printing inks, which can comprise pigment dispersionscomprising the inventive maleimides I or can be prepared for example bymixing a pigment dispersion comprising a maleimides I with chemically,thermally or photolytically structurable high molecular weight organicmaterial (so-called resist). The subsequent preparation can be carriedout, for example, in analogy to EP-A 654 711 by application to asubstrate, such as a LCD, subsequent photostructuring and development.

[0158] Particular preference for the production of color filters isgiven to pigment dispersions comprising a maleimides I which possessnon-aqueous solvents or dispersion media for polymers.

[0159] The present invention relates, moreover, to toners comprising apigment dispersion containing a maleimide I or a high molecular weightorganic material pigmented with a maleimide I in a coloristicallyeffective amount. In a particular embodiment of the process of theinvention, toners, coating materials, inks or colored plastics areprepared by processing masterbatches of toners, coating materials, inksor colored plastics in roll mills, mixing apparatus or grindingapparatus.

[0160] The present invention additionally relates to colorants, coloredplastics, polymeric ink particles, or non-impact-printing materialcomprising an inventive maleimide I pigment, preferably in the form of adispersion, or a high molecular weight organic material pigmented with amaleimide I in a coloristically effective amount.

[0161] A coloristically effective amount of the pigment dispersionaccording to this invention comprising an inventive maleimide I denotesin general from 0.0001 to 99.99% by weight, preferably from 0.001 to 50%by weight and, with particular preference, from 0.01 to 50% by weight,based on the overall weight of the material pigmented therewith.

[0162] Further, the inventive compounds I can be used for textileapplication and for the dying of paper.

[0163] A further embodiment of the present invention relates to the useof the fluorescent maleimides of the general formula I and of theformula Ia

[0164] for the preparation of and use in organic electroluminescent(“EL”) devices. Such EL devices are well-known in the art (e.g.described in Appl. Phys. Lett. 51 (1987) 913).

[0165] In a preferred embodiment EL devices are used which have thefollowing compositions:

[0166] (i) an anode/a hole transporting layer/an electron transportinglayer/a cathode

[0167] in which the inventive compounds I or compounds Ia are usedeither as positive-hole transport compounds, which is exploited to formthe light emitting and hole transporting layers, or as electrontransport compounds, which can be exploited to form the light-emittingand electron transporting layers, and

[0168] (ii) an anode/a hole transporting layer/a light-emitting layer/anelectron transporting layer/a cathode,

[0169] in which the inventive compounds I or compounds Ia form thelight-emitting layer regardless of whether they exhibit positive-hole orelectron transport properties in this constitution. It is possible thatthe light emitting layer can consist of two or more fluorescentsubstances of formulae I or Ia for energy donor(s) and energyacceptor(s).

[0170] The devices can be prepared in several well-known ways.Generally, vacuum evaporation is extensively used for the preparation.The devices can be prepared in several ways. Usually, vacuum evaporationis extensively used for the preparation. Preferably, the organic layersare laminated in the above order on a commercially availableindium-tin-oxide (“ITO”) glass substrate held at room temperature, whichworks as the anode in the constitutions. The membrane thickness ispreferably in the range of 1 to 10⁴ nm, more preferably 1 to 5000 nm,more preferably 1 to 10³ nm, more preferably 1 to 500 nm. The cathodemetal such as Mg/Ag alloy and Li—Al binary system of ca. 200 nm islaminated on the top of the organic layers. The vacuum during thedeposition is preferably less than 0.1333 Pa (1×10⁻³ Torr), morepreferably less than 1.333×10⁻³ Pa (1×10⁻⁵ Torr), more preferably lessthan 1.333×10⁻⁴ Pa (1×10⁻⁶ Torr).

[0171] As anode usual anode materials which possess high work functionsuch as metals like gold, silver, copper, aluminum, indium, iron, zinc,tin, chromium, titanium, vanadium, cobalt, nickel, lead, manganese,tungsten and the like, metallic alloys such as magnesium/copper,magnesium/silver, magnesium/aluminum, aluminum/indium and the like,semiconductors such as Si, Ge, GaAs and the like, metallic oxides suchas indium-tin-oxide (“ITO”), ZnO and the like, metallic compounds suchas Cul and the like, and furthermore, electroconducting polymers suchpolyacetylene, polyaniline, polythiophene, polypyrrole,polyparaphenylene and the like, preferably ITO, most preferably ITO onglass as substrate can be used. Of these electrode materials, metals,metallic alloys, metallic oxides and metallic compounds can betransformed into electrodes, for example, by means of the sputteringmethod. In the case of using a metal or a metallic alloy as a materialfor an electrode, the electrode can be formed also by the vacuumdeposition method. In the case of using a metal or a metallic alloy as amaterial forming an electrode, the electrode can be formed, furthermore,by the chemical plating method (see for example, Handbook ofElectrochemistry, pp 383-387, Mazuren, 1985) In the case of using anelectroconducting polymer, an electrode can be made by forming it into afilm by means of anodic oxidation polymerization method onto a substratewhich is previously provided with an electroconducting coating. Thethickness of an electrode to be formed on a substrate is not limited toa particular value, but, when the substrate is used as a light emittingplane, the thickness of the electrode is preferably within the range offrom 1 nm to 100 nm, more preferably, within the range of from 5 to 50nm so as to ensure transparency.

[0172] In a preferred embodiment ITO is used on a substrate having anITO film thickness in the range of from 10 nm (100 Å) to 1μ (10000 Å),preferably from 20 nm (200 Å) to 500 nm (5000 Å). Generally, the sheetresistance of the ITO film is chosen in the range of not more than 100Ω/cm², preferred from not more than 50 Ω/cm².

[0173] Such anodes are commercially available e.g. from e.g. Japanesemanufacturers such as Geomatech Co.Ltd., Sanyo Vacuum Co. Ltd., NipponSheet Glass Co. Ltd.

[0174] As substrate either an electroconducting or electricallyinsulating material can be used. In case of using an electroconductingsubstrate, a light emitting layer or a positive hole transporting layeris directly formed thereupon, while in case of using an electricallyinsulating substrate, an electrode is firstly formed thereupon and thena light emitting layer or a positive hole transporting layer issuperposed

[0175] The substrate may be either transparent, semi-transparent oropaque. However, in case of using a substrate as an indicating plane,the substrate must be transparent or semi-transparent.

[0176] Transparent electrically insulating substrates are, for example,inorganic compounds such as glass, quartz and the like, organicpolymeric compounds such as polyethylene, polypropylene,polymethylmethacrylate, polyacrylonitrile, polyester, polycarbonate,polyvinylchloride, polyvinylalcohol, polyvinylacetate and the like. Eachof these substrates can be transformed into a transparentelectroconducting substrate by providing it with an electrode accordingto one of the methods described above.

[0177] As examples of semi-transparent electrically insulatingsubstrates, there are inorganic compounds such as alumina, YSZ (yttriumstabilized zirconia) and the like, organic polymeric compounds such aspolyethylene, polypropylene, polystyrene, epoxy resin and the like. Eachof these substrates can be transformed into a semi-transparentelectroconducting substrate by providing it with an electrode accordingto one of the abovementioned methods.

[0178] As examples of opaque electroconducting substrates, there aremetals such as aluminum, indium, iron, nickel, zinc, tin, chromium,titanium, copper, silver, gold, platinum and the like, variouseletroplated metals, metallic alloys such as bronze, stainless steel andthe like, semiconductors such as Si, Ge, GaAs, and the like,electroconducting polymers such as polyaniline, polythiophene,polypyrrole, polyacetylene, polyparaphenylene and the like.

[0179] A substrate can be obtained by forming one of the above listedsubstrate materials to a desired dimension. It is preferred that thesubstrate has a smooth surface. Even if it has a rough surface, however,it will not cause any problem for practical use, provided that it hasround unevenness having a curvature of not less than 20 μm. As for thethickness of the substrate, there is no restriction as far as it ensuressufficient mechanical strength.

[0180] As cathode usual cathode materials which possess low workfunction such as alkali metals, earth alkaline metals, group 13elements, silver, and copper as well as alloys or mixtures thereof suchas sodium, lithium, potassium, sodium-potassium alloy, magnesium,magnesium-silver alloy, magnesium-copper alloy, magnesium-aluminumalloy, magnesium-indium alloy, aluminum, aluminum-aluminum oxide alloy,aluminum-lithium alloy, indium, calcium, and materials exemplified inEP-A 499,011 such as electroconducting polymers e.g. polypyrrole,polythiophene, polyaniline, polyacetylene etc., preferably Mg/Ag alloys,or Li—Al compositions can be used.

[0181] In a preferred embodiment magnesium-silver alloy or a mixture ofmagnesium and silver mixture, or lithium-aluminum alloy or a mixture oflithium and aluminum can be used in a film thickness in the range offrom 10 nm (100 Å) to 1 μm (10000 Å), preferably from 20 nm (200 Å) to500 nm (5000 Å).

[0182] Such cathodes can be deposited on the foregoing electrontransporting layer by known vacuum deposition techniques described above

[0183] In a preferred ambodiment of this invention a light-emittinglayer can be used between the hole transporting layer and the electrontransporting layer. Usually it is prepared by forming a thin film of amaleimide of formula I on the hole transporting layer.

[0184] As methods for forming said thin film, there are, for example,the vacuum deposition method, the spin-coating method, the castingmethod, the Langmuir-Blodgett (“LB”) method and the like. Among thesemethods, the vacuum deposition method, the spin-coating method and thecasting method are particularly preferred in view of ease in operationand cost. In case of forming a thin film using a fluorescent maleimide Iby means of the vacuum deposition method, the conditions under which thevacuum deposition is carried out are usually strongly dependent on theproperties, shape and crystalline state of the compound. However,optimum conditions can be selected for example within the range of from100 to 400° C. in temperature for the heating boat, −100 to 350° C. insubstrate temperature, 1.33×10⁴ Pa (1×10² Torr) to 1.33×10⁻⁴ Pa (1×10⁻⁶Torr) in pressure and 1 pm to 6 nm/sec in deposition rate.

[0185] In an organic EL element, the thickness of the light emittinglayer thereof is one of the factors determining its light emissionproperties. For example, if a light emitting layer is not sufficientlythick, a short circuit can occur quite easily between two electrodessandwiching said light emitting layer, and therefor, no EL emission isobtained. On the other hand, if the light emitting layer is excessivelythick, a large potential drop occurs inside the light emitting layerbecause of its high electrical resistance, so that the threshold voltagefor EL emission increases. Accordingly, it is necessary to limit thethickness of an organic light emitting layer within the range of from 5nm to 5 μm. A preferable thickness is within the range of from 10 nm to500 nm.

[0186] In the case of forming a light emitting layer by using thespin-coating method and the casting method, the coating can be carriedout using a solution prepared by dissolving the fluorescent maleimide Iin a concentration of from 0.0001 to 90% by weight in an appropriateorganic solvent such as benzene, toluene, xylene, tetrahydrofurane,methyltetrahydrofurane, N,N-dimethylformamide, dichloromethane,dimethylsulfoxide and the like Herein, the higher the concentration offluorescent maleimide I, the thicker the resulting film, while the lowerthe concentration, the thinner the resulting film. However, if theconcentration exceeds 90% by weight, the solution usually is so viscousthat it no longer permits forming a smooth and homogenous film. On theother hand, as a rule, if the concentration is less than 0.0001% byweight, the efficiency of forming a film is too low to be economical.Accordingly, a preferred concentration of the fluorescent maleimide I iswithin the range of from 0.01 to 80% by weight. In the case of using theabove spin-coating or casting method, it is possible to further improvethe homogeneity and mechanical strength of the resulting layer by addinga polymer binder in the solution for forming the light emitting layer.In principle, any polymer binder may be used, provided that it issoluble in a solvent in which the fluorescent maleimide I is dissolved.Examples of such polymer binders are polycarbonate, polyvinylalcohol,polymethacrylate, polymethylmethacrylate, polyester, polyvinylacetate,epoxy resin and the like. A solution for forming a light emitting layermay have any concentrations of the fluorescent maleimide I, of a polymerbinder and solvent. However, if the solid content composed of thepolymer binder and fluorescent maleimide I exceeds 99% by weight, thefluidity of the solution is usually so low that it is impossible to forma light emitting layer excellent in homogeneity. On the other hand, ifthe content of fluorescent maleimide I is substantially smaller thanthat of the polymer binder, in general the electrical resistance of saidlayer is very large, so that it does not emit light unless a highvoltage is applied thereto. Furthermore, since the concentration offluorescent maleimide I in the layer is small in this case, its lightemission efficiency is relatively low. Accordingly, the preferredcomposition ratio of a polymer binder to fluorescent maleimide I ischosen within the range of from 10:1 to 1:50 by weight, and the solidcontent composed of both components in the solution is preferably withinthe range of from 0.01 to 80% by weight, and more preferably, within therange of about 0.1 to 60% by weight.

[0187] In the case of forming a light emitting layer by the spin-coatingmethod or casting method, the thickness of said layer may be selected inthe same manner as in the case of forming a light emitting layer by thevacuum deposition method. That is, the thickness of the layer preferablyis chosen within the range of from 5 nm to 5 μm, and more preferably,within the range of from 10 nm to 500 nm.

[0188] As hole-transporting layers known organic hole transportingcompounds such as polyvinyl carbazole,

[0189] a triphenylamine derivative (“TPD”) compound disclosed inJ.Amer.Chem.Soc. 90 (1968) 3925

[0190] wherein Q₁ and Q₂ each represent a hydrogen atom or a methylgroup; a compound disclosed in J. Appl. Phys. 65(9) (1989) 3610

[0191] a stilbene based compound

[0192] wherein T and T₁ stand for an organic rest a hydrazone basedcompound

[0193] and the like

[0194] Compounds to be used as a positive hole transporting material arenot restricted to the above listed compounds. Any compound having aproperty of transporting positive holes can be used as a positive holetransporting material such as triazole derivatives, oxadiazolederivatives, imidazole derivatives, polyarylalkane derivatives,pyrazoline derivative, pyrazolone derivatives, phenylene diaminederivatives, arylamine derivatives, amino substituted chalconederivatives, oxazole derivatives, stilbenylanthracene derivatives,fluorenone derivatives, hydrazone derivatives, stilbene derivatives,copolymers of aniline derivatives, electro-conductive oligomers,particularly thiophene oligomers, porphyrin compounds, aromatic tertiaryamine compounds, stilbenyl amine compounds etc. Particularly, aromatictertiary amine compounds such asN,N,N′,N′-tetraphenyl-4,4′-diaminobiphenyl,N,N′-diphenyl-N,N′-bis(3-methylphenyl)-4,4′-diaminobiphenyl (TPD),2,2′-bis(di-p-torylaminophenyl)propane,1,1′-bis(4-di-torylaminophenyl)-4-phenylcyclohexane,bis(4-dimethylamino-2-methylphenyl)phenylmethane,bis(4-di-p-tolylaminophenyl)phenylmethane,N,N′-diphenyl-N,N′-di(4-methoxyphenyl)-4,4′-diaminobiphenyl,N,N,N′,N′-tetraphenyl-4,4′-diaminodiphenylether,4,4′-bis(diphenylamino)quaterphenyl, N,N,N-tri(p-tolyl)amine,4-(di-p-tolylamino)-4′-[4-(di-p-tolylamino)stilyl]stilbene,4-N,N-diphenylamino-(2-diphenylvinyl)benzene,3-methoxy-4′-N,N-diphenylaminostilbene, N-phenylcarbazole etc.

[0195] Furthermore, 4,4′-bis[N-(1-naphtyl)-N-phenylamino]biphenyldisclosed in U.S. Pat. No. 5,061,569, the compounds in which threetriphenylamine units are bound to a nitrogen atom like “star-burst”structure e.g.4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine disclosedin EP-A 508,562.

[0196] A positive hole transporting layer can be formed by preparing anorganic film containing at least one positive hole transporting materialon the anode. The positive hole transporting layer can be formed by thevacuum deposition method, the spin-coating method, the casting method,the LB method and the like. Of these methods, the vacuum depositionmethod, the spin-coating method and the casting method are particularlypreferred in view of ease and cost.

[0197] In the case of using the vacuum deposition method, the conditionsfor deposition may be chosen in the same manner as described for theformation of a light emitting layer (see above). If it is desired toform a positive hole transporting layer comprising more than onepositive hole transporting material, the coevaporation method can beemployed using the desired compounds.

[0198] In the case of forming a positive hole transporting layer by thespin-coating method or the casting method, the layer can be formed underthe conditions described for the formation of the light emitting layer(see above).

[0199] As in the case of forming a light emitting layer using a solutioncontaining a polymer binder, a smoother and more homogeneous positivehole transporting layer can be formed by using a solution containing abinder and at least one positive hole transporting material. The coatingusing such a solution can be performed in the same manner as in cases offorming a light emitting layer using a polymer binder. Any polymerbinder may be used, provided that it is soluble in a solvent in which atleast one positive hole transporting material is dissolved. Examples ofappropriate polymer binders and of appropriate and preferredconcentrations are given above when describing the formation of a lightemitting layer.

[0200] The thickness of a positive hole transporting layer is preferablychosen in the range of from 0.5 to 1000 nm, preferably from 1 to 100 nm,more preferably from 2 to 50 nm.

[0201] As electron transporting materials for an electron-transportinglayer it is preferred to have a high electron injection efficiency fromthe cathode and a high electron mobility. The following materials can beexemplified for electron transporting materials:tris(8-hydroxyquinolinoato)aluminum(III) and its derivatives,bis(10-hydroxybenzo[h]quinolinolato)beryllium(II) and its derivatives,oxadiazole derivatives such as2-(4-biphenyl)-5-(4-tert.-butylphenyl)-1,3,4-oxadiazole and its dimersystems such as1,3-bis(4-tert.-butylphenyl-1,3,4)oxadiazolyl)biphenylene and1,3-bis(4-tert.-butylphenyl-1,3,4-oxadiazolyl)phenylene, triazolederivatives, phenanthroline derivatives or perylene tetracarboxylic acidderivatives such as disclosed in Appl Phys. Lett. 48 (2) (1986)183

[0202] An electron transporting layer can be formed by preparing anorganic film containing at least one electron transporting material onthe hole transporting layer or on the light-emitting layer The electrontransporting layer can be formed by the vacuum deposition method, thespin-coating method, the casting method, the LB method and the like.

[0203] As in the case of forming a light emitting layer or a positivehole transporting layer by using a solution containing a polymer binder,a smoother and more homogeneous electron transporting layer can beformed by using a solution containing a binder and at least one electrontransporting material.

[0204] The thickness of an electron transporting layer is preferablychosen in the range of from 0.5 nm to 1000 nm, preferably from 1 nm to100 nm, more preferably from 2 to 50 nm.

[0205] Another embodiment relates to the use of the inventive compoundsI and known compounds Ia as UV fluorescent materials for void detection.Especially preferred is the use for so-called OEM (original equipmentmanufacturer) applications such as automotive electrocoats andsubsequent layers, for example primer surfacers, as well as industrialapplications in general.

[0206] The present invention therefore relates to coating compositionscomprising (a) an organic film-forming binder and (b) at least onecompound of the formula I or Ia.

[0207] The coating composition is optionally solvent based, water basedor solvent free.

[0208] Examples of coating materials are lacquers, paints, varnishes,powder coatings or electrocoats. These usually contain an organicfilm-forming binder in addition to other, optional components.

[0209] Preferred organic film-forming binders are epoxy resins,polyurethane resins, amino resins, acrylic resins, acrylic copolymerresins, polyvinyl resins, phenolic resins, urea resins, melamine resins,styrene/butadiene copolymer resins, vinyl/acrylic copolymer resins,polyester resins or alkyd resins, or a mixture of two or more of theseresins, or an aqueous basic or acidic dispersion of these resins ormixtures of these resins, or an aqueous emulsion of these resins ormixtures of these resins, or hybrid systems based on, for example, epoxyacrylates

[0210] More specifically, the alkyd resins can be water-dilutable alkydresin systems which can be employed in air-drying form or in the form ofstoving systems, optionally in combination with water-dilutable melamineresins; the systems may also be oxidatively drying, air-drying orstoving systems which are optionally employed in combination withaqueous dispersions based on acrylic resins or copolymers thereof, withvinyl acetates, etc.

[0211] The acrylic resins can be pure acrylic resins, epoxy acrylatehybrid systems, acrylic acid or acrylic ester copolymers, combinationswith vinyl resins, or copolymers with vinyl monomers such as vinylacetate, styrene or butadiene. These systems can be air-drying systemsor stoving systems.

[0212] In combination with appropriate polyamine crosslinkers,water-dilutable epoxy resins exhibit excellent mechanical and chemicalresistance. If liquid epoxy resins are used, the addition of organicsolvents to aqueous systems can be omitted. The use of solid resins orsolid-resin dispersions usually necessitates the addition of smallamounts of solvent in order to improve film formation.

[0213] Preferred epoxy resins are those based on aromatic polyols,especially those based on bis-phenols The epoxy resins are employed incombination with crosslinkers. The latter may in particular be amino- orhydroxy-functional compounds, an acid, an acid anhydride or a Lewis acidor a blocked isocyanate. Examples thereof are polyamines,polyaminoamides, polysulfide-based polymers, polyphenols, boronfluorides and their complex compounds, polycarboxylic acids,1,2-dicarboxylic anhydrides, pyromellitic dianhydride, ot toluoyldi-isocyanates.

[0214] Polyurethane resins are derived from polyethers, polyesters andpolybutadienes with terminal hydroxyl groups, on the one hand, and fromaliphatic or aromatic polyisocyanates on the other hand.

[0215] Examples of suitable polyvinyl resins are polyvinylbutyral,polyvinyl acetate or copolymers thereof

[0216] Suitable phenolic resins are synthetic resins in the course ofwhose construction phenols are the principal component, i.e. inparticular phenol-, cresol-, xylenol- and resorcinol-formaldehyderesins, alkylphenolic resins, and condensation products of phenols withacetaldehyde, furfurol, acrolein or other aldehydes. Modified phenolicresins are also of interest.

[0217] The coating compositions may additionally comprise one or morecomponents taken, for example, from the group consisting of pigments,dyes, fillers, flow control agents, dispersants, thixotropic agents,adhesion promoters, antioxidants, light stabilizers and curingcatalysts.

[0218] The pigments are, for example, titanium dioxide, iron oxide,aluminium bronze or phthalocyanine blue.

[0219] Examples of fillers are talc, alumina, aluminium silicate,barytes, mica, and silica.

[0220] Flow control agents and thixotropic agents are based, forexample, on modified bentonites.

[0221] Adhesion promoters are based, for example, on modified silanes.

[0222] The claimed fluorescent compounds can be added to the coatingmaterial during its preparation, for example during pigment dispersionby grinding, or they are dissolved in a solvent and the solution is thenstirred into the coating composition.

[0223] In the preparation of the organic film-forming binder by additionpolymerization or condensation polymerization of monomers, the claimedfluorescent compounds can be mixed in in solid form, or dissolved, withthe monomers even prior to the polymerization reaction.

[0224] The inventive maleimides I and other compounds of the formula Iaas well as compounds belonging to the group of dyestuffs exhibiting edgefluorescence are used in amounts of preferably 0 01% to 5% by weight,more preferably from 0.5 to 1.0% by weight, based on the total solids ofthe formulation containing no fluorescent agent.

[0225] The coating materials can be applied to the substrate by thecustomary techniques, for example by spraying, dipping, spreading orelectrodeposition. In many cases, a plurality of coats are applied. Theclaimed maleimides I or the known compounds Ia as well as compoundsbelonging to the group of dyestuffs exhibiting edge fluorescence usuallyare added primarily to the base layer (primer), however, they can alsobe added to the intermediate coat, for example a primer surfacer, ortopcoat, as well. Depending on whether the binder is a physically,chemically or oxidatively drying resin or a heat-curing orradiation-curing resin, the coating is cured at room temperature or byheating (stoving) or by irradiation.

[0226] Once the coating compositions are cured, the correspondingcoatings can be inspected with the use of a UV-lamp. Defects or voids asa result of misapplication or artificially applied defects can be easilydetected, because the used fluorescent compounds exhibit intensefluorescence only at the voids (so-called “edge fluorescence”).

[0227] Hence, another preferred embodiment of this invention relates toa composition comprising a dyestuff exhibiting edge fluorescence.

[0228] A further preferred embodiment of this invention relates to amethod of inspecting the surface of a body comprising the steps of:

[0229] (a) covering a surface with a composition comprising a compoundexhibiting edge fluorescence,

[0230] (b) inspecting the thus covered surface with ultraviolet lightfor visible light, such being indicative of faults in the surface.

[0231] Preferably, inspection is done using a high intensity black light(UV-A, 320-400 nm), preferably under low light conditions. A suitablelamp is available from Spectronics Corporation Inc. (Westbury, N.Y.).

[0232] Preferably, the edge fluorescence exhibiting compound is amaleimide of formulae I or Ia are used, most preferably1,1′-(1,2-ethanediyl)bis[3,4-diphenyl]-1H-pyrrole-2,5-dione

[0233] A further preferred embodiment relates to an article ofmanufacture comprising: a body having a surface to be covered; a layerof coating material on the surface of the body, fluorescing meansblended with said coating material for emitting identifiable visiblelight in response to exposure to ultraviolet light.

[0234] Preferably, the fluorescing means is a compound of formula I orIa, particularly preferred is1,1′-(1,2-ethanediyl)bis[3,4-diphenyl]-1H-pyrrole-2,5-dione.

[0235] The claimed fluorescent compounds as well as the compositionsallow easy quality assurance, instant possibility of repair, easylonger-term inspection. Further, compared to optical brighteners, asuperior solubility is observed which makes an incorporation more easy.In addition, the claimed materials show fluorescence in the solid state,whereas optical brighteners must be soluble in the resin or polymer toexhibit fluorescence. The claimed compounds and compositions also show asuperior photostability and none to less yellowing compared to opticalbrighteners upon UV-exposure, i.e. optical brighteners photochemicallydecompose under UV-light within less than 24 to 100 hours with formationof colored products leading to discoloration of e.g. white coatings.Also the claimed compounds and compositions migrate less than andcontaminate the working environment less than optical brighteners. A bigadvantage is the exhibition of the so-called edge fluorescence meaningthat fluorescence is observed only at voids and not at the whole surfacewhich gives much better contrast compared to e.g. optical brightenersand allows also the detection of minor defects or damages. Too, theinventive compounds and composition have no or only minimal impact onthe paint color in comparison to dyes, i.e. they can be even used inwhite pigmented systems. Further, the inventive materials are useful indark and white pigmented systems where optical brighteners fail, i.e. indark pigmented systems fluorescence and subsequently voids are difficultto detect in known systems, in white pigmented systems fluorescence istoo intense (whole surface) which in turn makes it very difficult toidentify voids in systems of the prior art. Finally, the found superiorphotostability of the inventive materials compared to opticalbrighteners allows long-term void detection, i.e. inspection aftermonths or years after the application. Particularly,1,1′-(1,2-ethanediyl)bis[3,4-diphenyl]-1H-pyrrole-2,5-dione is suitablefor detecting defects such as craters (voids) and poor coverage: anunique edge fluorescence phenomenon is shown when a cured coating isscratched. The technique also works over uneven surfaces, e.g. weldseams.

Examples

[0236] (A) Preparation of Diarylmaleic Anhydrides

Example 1

[0237] (a) To 301 g (2.26 mol) of AlCl₃ in CH₂Cl₂ (750 ml) a mixture of383 g (2.25 mol) of 4-phenoxybenzene and 205 g (1.50 mol) of ethylchloroglyoxylate in CH₂Cl₂ (750 ml) is added dropwise at ice-bathtemperature during one hour. Thereafter, the mixture is gradually warmedup to room temperature and stirred overnight. Then, the reaction mixtureis poured onto ice. The aq. solution is acidified to pH 3 with aqueousHCl solution, followed by an extraction with CH₂Cl₂. The extract isdried over anhydrous MgSO₄. The desired product is purified by silicagel column chromatography using CH₂Cl₂-hexane mixture as eluent. 338 gof colorless oily 4-phenoxyphenyl glyoxylic acid ethyl ester is obtained(83%).

[0238] (b) 338 g (1.25 mol) of the above obtained product is treatedwith 60.4 g (1.45 mol) of NaOH (96%) in 1 l of water and 1 l of EtOHunder reflux for 2 h. The mixture is then acidified to pH 3, and then4-phenoxyphenyl glyoxylic acid is extracted with CH₂Cl₂. 310 g of oil isobtained as a crude product. This product is used for next the belowreaction without further purification.

[0239] (c) To 167 g of 4-phenoxyphenyl glyoxylic acid 160 ml (3.30 mol)of hydrazine monohydrate are carefully added through a condenser underreflux over 45 min. After cooling the reaction mixture to 100° C., 176 g(2.68 mol) of KOH (85% in water) are carefully added over 45 min., andthen the reaction mixture is heated to reflux for 45 min. Excesshydrazine is removed by distillation, and the mixture is acidified withdiluted aqueous HCl to pH 3, followed by an extraction with CH₂Cl₂. Thedesired 4-phenoxyphenyl acetic acid is purified by repeatedcrystallization from hot hexane. 122 g of white solid are obtained(80%).

[0240] (d) 142 g (582 mmol) of 4-phenoxyphenyl glyoxylic acid aretreated with 68.6 g (612 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt. The obtained white solid is then filtered,followed by washing with MeOH. 162 g of white solid are obtained. 150 g(535 mmol) of this white solid are mixed with 120 g (525 mmol) of4-phenoxyphenyl acetic acid in 1 l of acetic anhydride and heated toreflux for two hours. After removal of acetic anhydride by evaporationin an atmosphere under reduced pressure, the obtained yellow solid iswashed with acetone and ethyl acetate affording 217 g of yellow solid3,4-di(4-phenoxyphenyl) maleic anhydride (93%).

Examples 2a-13a

[0241] Example 1a is repeated with the differences mentioned in thebelow Table 1: TABLE 1 treatment stirring AlCl₃ in CH₂Cl₂ amount ethylchloro- in CH₂Cl₂ in ice-bath after warming Yield ex. [g] [ml] R₁₃—H [g]glyoxylate [g] [ml] [h] to r.t. [h] [%] 2a 68.4 300 3-dibenzofurane 51.245.0 400 1 2 89 3a 67.3 200 4-methoxybenzene 43.4 60.1 200 1 1 82 4a15.0 100 4-phenylthiobenzene 18.6 14.3 150 ½ 2/3 76 5a 14.9 3003,4-dimethoxybenzene 13.8 14.3 150 ½ 2/3 33    6a¹⁾ 23.0 604-dimethylaminobenzene 12.2 15.0 60 1/6 12 44    7a²⁾ 45.0 2004-diphenylaminobenzene 76.5 42.6 200 2/3 2 ½  47 8a 20.5 1503-(N-ethyl)-carbazole 19.5 14.4 150 ¼ 2 72 9a 23.44 60 1-naphthaline12.8 15.0 60 1 ½  12 92 10a  37.3 100 4-methoxy-1-naphthaline 25.5 23.9100  5/12  7/12 95 11a  22.1 100 4-morpholinobenzene 24.5 21.5 100 3 1243 12a  27.4 60 1-pyrene 24.3 18.1 60  5/12 12 83 13a  13.6 359-anthrene 10.8 9.10 65 1/6 12 84

Example 14a

[0242] To 8.56 g (60.2 mmol) of 3,4-ethylenedioxy-2-thiophene intetrahydrofurane (“THF”) (50 ml) 40 ml of 1.6 M n-BuLi hexane solution(64 mmol) are added dropwise at −100° C. over 10 min. The obtainedsolution is added to 17.6 g (121 mmol) of diethyl oxalate in THF (50 ml)at −100° C. through a canula during two hours. After completion of theaddition, the obtained mixture is gradually warmed up to roomtemperature and stirred for four hours. Then, an aqueous NH₄Cl solutionis added to this reaction mixture. After removal of THF and hexane, theproduct is extracted with CH₂Cl₂. The extract is dried over anhydrousMgSO₄. Then, the desired product is purified by silica gel columnchromatography using CH₂Cl₂-hexane mixture as eluent. 12.2 g of yellowsolid 3,4-ethylenedioxy-2-thienyl glyoxylic acid ethyl ester areobtained (84%).

Example 15a

[0243] To 10.1 g (48.8 mmol) of naphthalene in 200 ml THF 65 ml of 1.6 Mn-BuLi hexane solution (104 mmol) are added dropwise at −100° C. during20 min. The obtained solution is added to 30 ml (221 mmol) of diethyloxalate during 5 min. After completion of the addition, the obtainedmixture is gradually warmed up to room temperature and stirred for 17.5hours. Then, water is added to this reaction mixture. After removal ofTHF and hexane, the product is extracted with CH₂Cl₂. The extract isdried over anhydrous MgSO₄. Then, the desired product is purified bysilica gel column chromatography using CH₂Cl₂-hexane mixture as eluent.3.76 g of yellow oil 2-naphthyl glyoxylic acid ethyl ester as a mixturetogether with diethyl oxalate. A ¹H-NMR-spectrum of the mixtureindicated the presence of the desired product with 56.4% in the mixture(19.1% yield). The mixture is used for the next reaction step (example15b) without any further purification.

Examples 2b to 16b

[0244] example 1 b is repeated, however, the reaction parameters ofTable 2 are used (ex. 16b, 4-acetylaminophenyl glyoxylic acid ethylester, is prepared according to the method described in J. Org. Chem.,1981, 46, 134) TABLE 2 duration ester VIII R₁₈ amount NaOH water EtOH ofreflux yield ex. (R₂₀ = ethyl) [g] [g] [ml] [ml] [h] workup [%] 2b3-dibenzofuryanyl 71.6 12.4 200 200 3 A 83 3b 4-methoxyphenyl 53.0 12.2250 250 1 B 93 4b 4-phenylthiophenyl 20.6 3.29 70 70 4 C 63 5b3,4-dimethoxyphenyl 7.58 1.51 30 30 1 D 90 6b 4-dimethylaminophenyl 9.582.63 50 50 5 E 56 7b 4-diphenylaminophenyl 50.6 6.76 150 150 2 D 95 8b3-(N-ethyl)-carbazo1e 20.9 3.29 70 70 3 D 100 9b 1-naphthyl 20.9 5.85100 100 3 ½ D 95 10b  4-methoxy-1-naphthyl 39.3 6.98 150 150 2 F 91 11b 4-morpholinophenyl 16.7 2.96 60 60 1 ½ G 93 12b  1-pyrenyl 29.7 4.51 100100 4 H 62 13b  9-anthryl 13.6 2.29 60 60 1 I 99 14b 3,4-ethylenedioxy-2-thienyl 12.0 2.17 50 50 4 J 89 15b  2-naphthyl 3.761.49 40 40 2 K 90

[0245] Workup

[0246] A: The mixture is acidified to pH 3, and then the product iscollected by filtration and subsequent washing with water and thenCH₂Cl₂.

[0247] B: The mixture is acidified to pH 3, and then the product iscollected by filtration and subsequent washing with water.

[0248] C: The mixture is acidified to pH 3, and then the product isextracted with CH₂Cl₂. The extract is dried over anhydrous MgSO₄. Thedesired product is purified by silica gel column chromatography usingCH₂Cl₂—MeOH mixture as eluent. 11.6 g of a brown oil are obtained.

[0249] D: The mixture is acidified to pH 3, and then the product isextracted with CH₂Cl₂. After removal of CH₂Cl₂, washing with hexaneaffords 11.6 g of a white solid.

[0250] E: After acidifying the mixture, the resulting solid is filteredoff, followed by washing with water and acetone. The desired product ispurified by silica gel column chromatography using CH₂Cl₂—MeOH mixtureas eluent. 4.65 g of a yellow solid are obtained.

[0251] F: The mixture is acidified, and then the product is extractedwith CH₂Cl₂. The extract is dried over anhydrous MgSO₄. After removal ofthe solvent, 32.0 g of a pale yellow solid are obtained.

[0252] G: The mixture is acidified to pH 3, and then the resulting whitesolid is filtered, foloowed by washing with water and acetone. 15.1 g ofa white solid are obtained as a crude product. This product is used forthe next reaction step without further purification.

[0253] H: The mixture is acidified to pH 3, and then the resulting whitesolid is filtered, followed by washing with water, acetone, and CH₂Cl₂.16.8 g of a yellow solid are obtained as a crude product. This productis used for the next reaction step without further purification.

[0254] I: The mixture is acidified, and then the product is extractedwith CH₂Cl₂. The extract is dried over anhydrous MgSO₄. After removal ofthe solvent, 12.1 g of an orange solid are obtained.

[0255] J: The mixture is acidified, and then the resulting solid isfiltered, followed by washing with water and a small portion of CH₂Cl₂.9.47 g of a yellow solid are obtained.

[0256] K: The mixture is acidified, and then the product is extractedwith CH₂Cl₂. The desired acid is purified by silica gel columnchromatography using CH₂Cl₂—MeOH mixture as eluent. 1.94 g of a yellowsolid are obtained.

Examples 2c to 15c, and 19c

[0257] example 1c is repeated, however, the educts and reactionparameters of Table 3 are used (2-4-methoxyphenyl)-acetic acid(corresponding to ex. 3c), 2-(3,4-dimethoxyphenyl)-acetic acid(corresponding to ex. 5c), 2-(4-diphenylaminophenyl)-acetic acid(corresponding to ex. 6c), 2-(1-naphthyl)-acetic acid (corresponding toex. 9c), 2-(2-naphthyl)-acetic acid (corresponding to ex. 15c) andchlorophenylacetic acid (corresponding to ex. 19c) are commerciallyavailable): TABLE 3 duration duration acid VI amount H₂NNH₂—H₂O ofreflux KOH of reflux yield ex. R₁₈ [g] [ml] [min] [g] [h] workup [%] 2c3-dibenzofuryanyl 24.1 35 20 26.5 3 A 57 4c 4-phenylthiophenyl 6.31 9 307.06 4 A 89 7c 4-diphenylaminophenyl 25.3 35 90 21.1 2 B 94 8c3-(N-ethyl)-carbazole 9.41 12.5 60 9.83 2 ½ C + C1 90 10c 4-methoxy-1-naphthyl 15.1 23 30 17.4 1 C + C2 97 11c  4-morpholinophenyl8.00 15 90 8.82 1 A 65 12c  1-pyrenyl 8.79  ^( 7.8) ¹⁾ 90   ^( 8.44) ²⁾2 B 23 14c  3,4-ethylenedioxy-2-thienyl 5.48 9.0 60 7.18 2 A 76

[0258] Workup

[0259] A Excess hydrazine is removed by distillation, and then themixture is acidified with diluted HCl to pH 3 The product is thenextracted with CH₂Cl₂. The desired acid is purified by silica gel columnchromatography using a CH₂Cl₂—MeOH mixture as eluent.

[0260] B: Excess hydrazine is removed by distillation, and then themixture is acidified with diluted HCl. The product is then extractedwith CH₂Cl₂. The desired acid is purified by silica gel columnchromatography using a CH₂Cl₂-acetone mixture as eluent.

[0261] C. Excess hydrazine is removed by distillation, and then themixture is acidified with diluted HCl. The product is then extractedwith CH₂Cl₂. Then, CH₂Cl₂ is removed by distillation.

[0262] C1: 9.18 g of a brownish solid are obtained as a crude product.This product is used for the next reaction step without furtherpurification.

[0263] C2: 13.8 g of a white solid are obtained.

Example 2d

[0264] 13.6 g (56.7 mmol) of the product obtained in ex. 2b are treatedwith 6.70 g (59.7 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, and then the solvent is removed byevaporation. After drying under an atmosphere of reduced pressure, theobtained solid is mixed with 12.8 g (56.7 mmol) of the product obtainedin ex. 2c and 110 ml of acetic anhydride and thereafter heated to refluxfor one hour. After removal of acetic anhydride by evaporation under anatmosphere of reduced pressure, the resulting yellow solid is washedwith acetone, affording 11.0 g (45%) of a yellow solid.

Example 3d

[0265] 41.8 g (232 mmol) of the product obtained in ex. 3b are treatedwith 27.7 g (247 mmol) of tert.-BuOK in MeOH to obtain the correspondingpotassium salt, and then the solvent is removed by evaporation. Afterdrying under an atmosphere of reduced pressure, the obtained solid ismixed with 39.5 g (235 mmol) of p-methoxyphenylacetic acid (commerciallyavailable, corr. to ex. 3c, 99% purity) in 460 ml of acetic anhydrideand then heated to reflux for 1.5 hours. Thereafter, acetic anhydride isremoved by evaporation in an atmosphere of reduced pressure. Theresulting solid is then washed with a hexane-acetone mixture, affording74.3 g of an orange solid (100%).

Example 4d

[0266] 4.44 g (17.2 mmol) of the product obtained in ex. 2b are treatedwith 2.03 g (18.0 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the residue under an atmosphere of reducedpressure, the obtained solid is mixed with 4.20 g (17.2 mmol) of theproduct obtained in ex 4c in 35 ml of acetic anhydride and heated toreflux for 1.5 hours After removal of acetic anhydride by evaporation inan atmosphere of reduced pressure, the resulting solid is washed withMeOH. The desired product is purified by silica gel columnchromatography using CH₂Cl₂-hexane mixture as eluent. 3.38 g of a yellowsolid are obtained (42%).

Example 5d

[0267] 4.22 g (20.1 mmol) of the product obtained in ex. 5b are treatedwith 2.37 g (21.1 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the residue under an atmosphere of reducedpressure, the obtained solid is mixed with 3.95 g (20.1 mmol) ofhomoveratric acid (commercially available, corresponding to ex. 5c) in40 ml of acetic anhydride and heated to reflux for 3.5 hours. Afterremoval of acetic anhydride by evaporation in an atmosphere of reducedpressure, the desired product is purified by silica gel columnchromatography using CH₂Cl₂ as eluent. 3.23 g of an orange solid areobtained (44%).

Example 6d

[0268] 1.97 g (10.2 mmol) of the product obtained in ex. 6b are treatedwith 1.23 g (11.0 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying under an atmosphere of reduced pressure, theobtained solid is mixed with 1.91 g (10.3 mmol) ofp-dimethylaminophenylacetic acid (commercially available, corr. to ex6c) in 20 ml of acetic anhydride and heated to reflux for 1.5 hours.After removal of acetic anhydride by evaporation in an atmosphere ofreduced pressure, the desired product is purified by silica gel columnchromatography using hexane-CH₂Cl₂ mixture as eluent 1.39 g of a darkred solid are obtained (41%).

Example 7d

[0269] 18.9 g (59.4 mmol) of the product obtained in ex. 7b are treatedwith 7.00 g (62.4 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the residue under an atmosphere of reducedpressure, the obtained solid is mixed with 18.1 g (59.7 mmol) of theproduct obtained in ex. 7c in 120 ml of acetic anhydride and heated toreflux for 1.5 hours. After removal of acetic anhydride by evaporationin an atmosphere of reduced pressure, the resulting solid is washed withacetone 24.3 g of a dark red solid are obtained (70%).

Example 8d.

[0270] 8.40 g (31.4 mmol) of the product obtained in ex. 8b are treatedwith 3.73 g (33.3 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying under an atmosphere of reduced pressure, theobtained solid is mixed with 8.00 g (31.6 mmol) of the product obtainedin ex. 8c in 60 ml of acetic anhydride and heated to reflux for 7 hours.After removal of acetic anhydride by evaporation in an atmosphere ofreduced pressure, the resulting solid is dissolved in CH₂Cl₂, and thenpurified by silica gel column chromatography using CH₂Cl₂-hexane mixtureas eluent. 7.92 g of a red solid are obtained (52%). by silica gelcolumn chromatography using hexane-ethyl acetate mixture as eluent. 20.9g of slightly brownish oil is obtained (92%).

Example 9d

[0271] 10.3 9 (51.5 mmol) of the product obtained in ex. 9b are treatedwith 6.04 g (53.8 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the obtained residue under an atmosphere ofreduced pressure, the obtained solid is mixed with 9.36 g (50.3 mmol) of1-naphthylacetic acid (commercially available, corr. to ex. 9c) in 100ml of acetic anhydride and heated to reflux for 14 hours. After removalof acetic anhydride by evaporation under an atmosphere of reducedpressure, the resulting solid is dissolved in CH₂Cl₂. This mixture thenis treated using silica gel column chromatography with a CH₂Cl₂-hexanemixture as eluent to obtain 5.47 g of a yellow solid (31%).

Example 10d

[0272] 14.6 g (63.3 mmol) of the product obtained in ex. 10b are treatedwith 7.36 g (65.6 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the obtained residue under an atmosphere ofreduced pressure, the obtained solid is mixed with 13.6 g (62.9 mmol) ofthe product obtained in ex 10c in 130 ml of acetic anhydride and heatedto reflux for 2 hours After removal of acetic anhydride by evaporationunder an atmosphere of reduced pressure, the resulting solid isdissolved in CH₂Cl₂. This mixture then is treated using silica gelcolumn chromatography with a hexane-ethyl acetate mixture as eluent toobtain 16.4 g of a brownish orange solid (63%).

Example 11d

[0273] 4.95 g (20.8 mmol) of the product obtained in ex. 11b are treatedwith 2.49 g (22.2 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed by evaporationAfter drying the obtained residue under an atmosphere of reducedpressure, the obtained white solid is mixed with 4.61 g (20.8 mmol) ofthe product obtained in ex. 11c in 40 ml of acetic anhydride and heatedto reflux for 1.5 hours. After removal of acetic anhydride byevaporation under an atmosphere of reduced pressure, the resultingyellow solid is washed with acetone and then dissolved in CH₂Cl₂. Thismixture then is treated using silica gel column chromatography with aCH₂Cl₂-acetone mixture as eluent to obtain 6.41 g of a yellow solid(74%).

Example 12d

[0274] 1.66 g (6.05 mmol) of the product obtained in ex. 12b are treatedwith 716 mg (6.38 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the thus obtained residue under an atmosphereof reduced pressure, the obtained solid is mixed with 1.56 g (6.00 mmol)of the product obtained in ex. 12c in 12 ml of acetic anhydride andheated to reflux for 1.5 hours. After removal of acetic anhydride byevaporation under an atmosphere of reduced pressure, the resulting redsolid is washed with acetone, thereafter extracted with hot CHCl₃ usinga Soxhlet extractor. 2.13 g of a red solid are obtained (71%).

Example 13d

[0275] 2.51 g (10.0 mmol) of the product obtained in ex. 13b are treatedwith 1.17 g (10.4 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the thus obtained residue under an atmosphereof reduced pressure, the obtained solid is mixed with 1.70 g (10.1 mmol)of p-methoxyphenylacetic acid (commercially available, corr. to ex. 3d)in 20 ml of acetic anhydride and heated to reflux for 2 hours. Afterremoval of acetic anhydride by evaporation under an atmosphere ofreduced pressure, the resulting solid is then dissolved in CH₂Cl₂. Thismixture then is treated using silica gel column chromatography with ahexane-ethyl acetate mixture as eluent to obtain 160 mg of a red solid(4.2%).

Example 14d

[0276] 3.58 g (16.7 mmol) of the product obtained in ex. 14b are treatedwith 1.90 g (16.9 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the obtained residue under an atmosphere ofreduced pressure, the obtained solid is mixed with 3.33 g (16.6 mmol) ofthe product obtained in ex. 14c in 30 ml of acetic anhydride and heatedto reflux for 3 hours. After removal of acetic anhydride by evaporationunder an atmosphere of reduced pressure, the resulting solid isdissolved in CH₂Cl₂. This mixture is treated using silica gel columnchromatography with a CH₂Cl₂-hexane mixture as eluent to obtain 1.72 gof a brown solid (27%).

Example 15d

[0277] 1.80 g (8.62 mmol) of the product obtained in ex. 15 b aretreated with 1.06 g (9.46 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the thus obtained residue under an atmosphereof reduced pressure, the obtained solid is mixed with 1.61 (8.64 mmol)of 2-naphthylacetic acid (commercially available, corr. to ex. 15c) in20 ml of acetic anhydride and heated to reflux for 3 hours. Afterremoval of acetic anhydride by evaporation under an atmosphere ofreduced pressure, the resulting solid is dissolved in CH₂Cl₂. Thismixture then is treated using silica gel column chromatography with aCH₂Cl₂-hexane mixture as eluent to obtain 0.36 g of a yellow solid(12%).

Example 16d

[0278] 4.51 g (29.8 mmol) of 4-acetylaminophenyl glyoxylic acid(commercially available) are treated with 3.46 g (30.8 mmol) oftert.-BuOK in MeOH to obtain the corresponding potassium salt, then thesolvent is removed by evaporation. After drying the residue under anatmosphere of reduced pressure, the obtained solid is mixed with 4.51 g(29.8 mmol) of p-aminophenylacetic acid in 60 ml of acetic anhydride andheated to reflux for two hours. After removal of acetic anhydride byevaporation in an atmosphere of reduced pressure, the desired product ispurified by silica gel column chromatography using CH₂Cl₂-acetonemixture as eluent, obtaining 0.56 g of a yellow-orange solid (5.3%).

Example 17d

[0279] 2.81 g (10.0 mmol) of the potassium salt (obtained by: 2.44 g (10mmol) of the product obtained in ex. 1b are treated with 1.23 g (11mmol) of tert.-BuOK in MeOH) of the product obtained in ex. 1b are mixedwith 1.82 g (9.82 mmol) of p-dimethylaminophenylacetic acid(commercially available, corr. to ex. 6c) in 20 ml of acetic anhydrideand heated to reflux for 2 hours. After removal of acetic anhydride byevaporation under an atmosphere of reduced pressure, the resultingyellow solid is washed with a CH₂Cl₂-hexane mixture, which afforded 3.18g of a dark red solid (84%).

Example 18d

[0280] 4.25 g (15.2 mmol) of potassium salt (obtained by: 3.71 g (15.2mmol) of the product obtained in ex. 1b are treated with 1.85 g (16.5mmol) of tert.-BuOK in MeOH) of the product obtained in ex. 1b are mixedwith 4.60 g (15.2 mmol) of the product obtained in ex. 7c in 30 ml ofacetic anhydride and heated to reflux for 1.5 hours After removal ofacetic anhydride by evaporation under an atmosphere of reduced pressure,the thus obtained resulting solid is dissolved in CH₂Cl₂. This mixture,then, is treated using silica gel column chromatography with ahexane-CH₂Cl₂ mixture as eluent. 6.12 g of a dark red solid are obtained(79%).

Example 19d

[0281] 9.85 g (30.1 mmol) of the product obtained in ex. 7b (97% pure)are treated with 3.53 g (31.5 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the thus obtained residue under an atmosphereof reduced pressure, the obtained solid is mixed with 5.40 g (31.7 mmol)of p-chlorophenylacetic acid (commercially available, corr. to 19c) in60 ml of acetic anhydride and heated to reflux for 1.5 hours. Afterremoval of acetic anhydride by evaporation under an atmosphere ofreduced pressure, the resulting solid is dissolved in CH₂Cl₂. Thismixture is treated using silica gel column chromatography with ahexane-CH₂Cl₂ mixture as eluent to obtain 9.54 g of a dark red solid(70%).

Example 20d

[0282] 6.97 g (22.0 mmol) of the product obtained in ex. 7b (97% pure)are treated with 2.62 g (23.4 mmol) of tert.-BuOK in MeOH to obtain thecorresponding potassium salt, then the solvent is removed byevaporation. After drying the thus obtained residue under an atmosphereof reduced pressure, the obtained solid is mixed with 4.70 g (21.7 mmol)of the product obtained in ex. 10c in 45 ml of acetic anhydride andheated to reflux for 2 hours. After removal of acetic anhydride byevaporation under an atmosphere of reduced pressure, the resulting solidis dissolved in CH₂Cl₂. This mixture then is treated using silica gelcolumn chromatography with a hexane-CH₂Cl₂ mixture as eluent to obtain6.52 g of a red solid (60%).

Example 21d

[0283] 8.30 g (28.0 mmol) of the potassium salt (obtained by: 8.0 g (28mmol) of the product obtained in ex. 4b are treated with 3.45 g (30.8mmol) of tert.-BuOK in MeOH) of the product obtained in ex. 4b are mixedwith 6.04 g (27.9 mmol) of the product obtained in ex. 10c in 60 ml ofacetic anhydride and heated to reflux for 2 hours. After removal ofacetic anhydride by evaporation under an atmosphere of reduced pressure,the resulting solid is dissolved in CH₂Cl₂. This mixture is treatedusing silica gel column chromatography with a hexane-CH₂Cl₂ mixture aseluent to obtain 7.56 g of a red solid (62%).

[0284] (B) Preparation of N-alkyldiarylmaleimides

[0285] General

[0286] 4 mmol of the corresponding diarylmaleic anhydride of formula Vand an excess (>4 mmol per each amino group) of the corresponding amineare heated to reflux in 20 ml of a mixture of toluene-DMF (3:1) forseveral hours. After removal of the solvents in an atmosphere underreduced pressure, the product is purified by column chromatography(silica gel with CH₂Cl₂-hexane as eluent).

Example 22

[0287] A mixture of 20.02 g (80 mmol) of diphenylmaleic anhydride and2.4 g (40 mmol) of 1,2-ethlenediamine in toluene-DMF (1:1, 300 ml) isheated to reflux for 4 hours. After removal of the solvent mixture in anatmosphere under reduced pressure, the obtained crude solid is washedtwice with each 100 ml of acetone. After drying, 19.72 g (94%) of alemon yellow solid are obtained.

Example 23

[0288] 4.4 g (10 mmol) of the product obtained in example 1d are treatedwith 310 mg of 1,2-ethlenediamine (5.2 mmol) in toluene-DMF (3:1, 50 ml)and heated under reflux for 6 hours. After removal of the solvents in anatmosphere under reduced pressure, the desired product is purified bycolumn chromatography (silica gel, CH₂Cl₂-haxane mixture as eluent).TABLE 4 compounds of formula IV (R₁₃ = R₁₄ = R₁₆ = R₁₇) Yield exampleR₁₃ R₁₅ (%) Colour Mp. (° C.) 22 phenyl 1,2- 94 lemon- >250 ethyleneyellow 23 4- 1,2- 92 Yellow 115.2-117.0 phenoxyphenyl ethylene

Example 24

[0289] 4.4 g (10 mmol) of the product obtained in example 1d are treatedwith 6.0 g of 1,2-ethlenediamine (100 mmol) in toluene-DMF (3:1, 50 ml)and heated to reflux for 3 hours. After removal of the solvents in anatmosphere under reduced pressure, a yellowish-orange product iscollected by column chromatography (silica gel, ethylacetate as eluent).This compound is treated with 1 ml acetic anhydride in 10 ml toluene atroom temperature for 23 hours The desired product is purified by columnchromatography (silica gel, ethylacetate/hexane mixture as eluent).

Example 25

[0290] 4.1 mmol of 3,4-diphenoxyphenyl maleic anhydride (from example1d) and 41 mmol of AcONH₄ are heated to reflux in acetic acid (20 ml)overnight. After condensation of the reaction mixture, the resultingsolid is filtered and washed with H₂O and MeOH. The product is purifiedby column chromatography (silica gel, CH₂Cl₂ as eluent).

Example 26-28

[0291] Example 25 is repeated, however, in example 263,4-di(4-diphenylaminophenyl) maleic anhydride, in example 273,4-di(4-methoxy-1-naphthyl) maleic anhydride, and in example 283,4-diphenyl maleic anhydride are used. TABLE 5 compounds of formula IIYield Example R₉ R₁₀ (%) Colour Mp. (° C.) 25 4-phenoxy- H 96 Yellow242.5-244.8 phenyl 26 4-diphenyl- H 68 Dark Red 244.3-246.5 aminophenyl27 4-methoxy- H 77 Orange 239.6-242.1 1-naphthyl 28 phenyl H 91 Pale217.5-218.4 Yellow

Example 29

[0292] 460 mg (1.1 mmol) of the product obtained in ex. 25 are treatedwith 47 mg of NaH (1.2 mmol) in 5 ml of DMF at room temperature for 20min. Into this reaction mixture 1,3-dibromopropane (1.0 ml, 9.9 mmol)are added and the mixture is stirred for one day at room temperature.After adding 20 ml of H₂O, the reaction mixture is extracted withCH₂Cl₂. The combined CH₂Cl₂-extracts are treated using columnchromatography (silica gel, CH₂Cl₂-hexane mixture as eluent).

Example 30

[0293] 949 mg of 1-pyrenemethanol (4.00 mmol) is treated with 2.0 g (6.0mmol) CBr₄ and 1.27 g (4.9 mmol) PPh₃ in 40 ml CH₂Cl₂ at roomtemperature for three hours. 20 ml of an saturated aqueous NaHCO₃solution is added to the reaction mixture, then the reaction mixture isextracted with CH₂Cl₂. After removal of CH₂Cl₂, the residue is added tothe potassium salt of the product obtained in ex. 25, which is preparedfrom 1.98 g (4.57 mmol) of the product obtained in ex. 25 by treatmentwith 520 mg of tert.-BuOK (4.63 mmol) in 10 ml of DMF at roomtemperature for 5 min. This mixture is stirred for one day at roomtemperature. After adding 10 ml of H₂O, the reaction mixture isextracted with CH₂Cl₂. The extracts are then treated using columnchromatography (silica gel, hexane-Et₂O (10:1) mixture as eluent). TABLE6 compounds of formula II Yield example R₉ R₁₀ (%) Colour Mp. (° C.) 244-phenoxy- 2- 12 yellow 71.7-75.0 phenyl acetylaminoethyl 29 4-phenoxy-3- 90 yellow 148.1-152.1 phenyl bromopropyl 30 4-phenoxy- 1- 49 yellow203.5-205.8 phenyl pyrenylmethyl

Example 31

[0294] A mixture of 5.00 g (20 mmol) of diphenylmaleic anhydride and2.02 mg (22 mmol) of cyclohexylamine are heated to reflux in a mixtureof toluene (150 ml) and DMF (150 ml) for five hours. After removal ofthe solvent mixture in an atmosphere under reduced pressure, 50 ml ofmethanol are added to solidify the material. The product is collected byfiltration, then washed with methanol. Yield: 4.7 g (71%) of alemon-yellow solid.

[0295] Similarly to the above mentioned examples the following compoundsare synthesized: TABLE 7 compounds of formula II Yield example R₉ R₁₀(%) Colour Mp. (° C.) 31 phenyl cyclohexyl 71 lemon- 159.6-160.3 yellow32 phenyl 2-amino- 65 Yellow >250 ethyl 33 phenyl isopropyl 80 lemon-135.3-137.3 yellow 34 phenyl 2-amino- 99 Yellow 158.5-160.1 cyclohexyl35 phenyl allyl 62 Yellow 89.2-92.0 36 3,4- cyclohexyl 78 Orange102.1-104.2 ethylene- dioxy- 2-thienyl 37 4-methoxy- cyclohexyl 52Yellow  96.7-100.4 phenyl 38 1-naphthyl cyclohexyl 90 Yellow 103.2-108.839 4-phenoxy- cyclohexyl 92 Greenish- 183.9-186.1 phenyl yellow 404-dimethyl- cyclohexyl 79 Dark red 229.9-232.0 amino- phenyl 414-phenoxy- isopropyl 86 Yellow 100.9-102.6 phenyl 42 4-phenoxy- tris 100Yellow 148.3-150.6 phenyl (hydroxy- methyl)- methyl 43 4-diphenyl-cyclohexyl 63 Reddish- 205.2-208.6 amino- orange phenyl 44 4-methoxy-cyclohexyl 84 Yellowish- 151.0-155.2 1-naphthyl orange 45 4-acetyl-cyclohexyl 90 Yellow 164.5-168.5 amino- phenyl 46 4-diphenyl- isopropyl75 Orange 212.8-213.6 amino- phenyl 47 3,4- cyclohexyl 95 Orange135.3-136.9 dimethoxy- phenyl 48 4-phenoxy- methyl 80 Yellow 134.2-136.4phenyl 49 4-phenoxy- trans-4- 29 Yellow 162.5-165.2 phenyl amino-cyclohexyl 50 4-diphenyl- 4-amino- 60 Reddish- 245.6-248.5 amino-cyclohexyl orange phenyl

[0296] TABLE 8 compounds of formula III Yield example R₁₁ R₁₂ R₁₃ (%)Colour Mp. (° C.) 51 4-phenoxyphenyl 4-dimethylamino- cyclohexyl 100 Red80.2-84.1 phenyl 52 4-phenoxyphenyl 4-dimethylamino- stearyl 90 Orange111.5-113.6 phenyl 53 4-methoxyphenyl 9-anthryl cyclohexyl 81 Yellowish-183.2-186.1 orange 54 3-dibenzofuranyl 2/3-dibenzofuranyl isopropyl 58Greenish- 218.0-222.2 yellow

[0297] TABLE 9 compounds of formula IV (R₁₃ = R₁₄ = R₁₆ = R₁₇) Yield Mp.example R₁₃ Rl5 (%) Colour (° C.) 55 4-phenoxy- trans-1,4-cyclo- 16Yellow >250 phenyl hexylene

[0298] and example 56, yielding a reddish-orange compound of the formula

[0299] with a yield of 84%, and a melting point of >250° C.

[0300] (C) Preparation of N-aryldiarylmaleimides

[0301] General: The corresponding diarylmaleic anhydride (4 mmol) andthe corresponding amine (>4 mmol) are heated to reflux in acetic acid(20 ml) for several hours. After removal of the solvents in anatmosphere under reduced pressure, the product is purified by columnchromatography (silica gel, CH₂Cl₂-haxane mixture as eluent).

Example 57

[0302] 280 mg (1.1 mmol) of diphenylmaleic anhydride are treated with110 mg of 2,5-di-tert.-butyl-1,4-phenylenediamine (0.51 mmol) in aceticacid (5.0 ml) and heated to reflux for 3 hours. After removal of thesolvents in an atmosphere under reduced pressure, the desired product ispurified by column chromatography (silica gel, CH₂Cl₂ as eluent).

Example 58

[0303] 920 mg of diphenylmaleic anhydride (3.7 mmol) and 260 mg of1,5-diaminonaphthalene (1.6 mmol) are refluxed in acetic acid (10 ml)for three hours. After removal of the solvents in an atmosphere underreduced pressure, the product is purified by column chromatography(silica gel, CH₂Cl₂ as eluent).

Example 59

[0304] 920 mg of diphenylmaleic anhydride (3.7 mmol) and 140 mg ofmelamine (1.1 mmol) are heated to reflux in acetic acid (10 ml) for 14hours. The resulting solid is collected by filtration, and the productis purified by column chromatography (silica gel, CH₂Cl₂-hexane aseluent) Yield: 60%, pale yellow compound, melting point 157.6-162.6° C.

Example 60

[0305] similarly a compound of formula II with R₉=phenyl andR₁₀=3-(hydroxymethyl)phenyl is prepared.

Example 61

[0306] similarly a compound of formula II with R₉=4-phenoxyphenyl andR₁₀=4-amino-2,5-dimethylphenyl is prepared.

Example 62

[0307] 6.5 g (18 mmol) of the product obtained in ex. 60 are treatedwith 9.2 g of CBr₄ (28 mmol) in the presence of PPh₃ (5.8 g, 22 mmol) in100 ml of CH₂Cl₂ at room temperature for 10 min After adding 20 ml of ansaturated aqueous NaHCO₃ solution, the reaction mixture is extractedwith CH₂Cl₂. The combined extracts are then treated using columnchromatography (silica gel, CH₂Cl₂-hexane mixture as eluent).

Example 63

[0308] 340 mg (1.0 mmol) of 3,4,9,10-perylenetetracarboxylicdianhydride, 460 g (2.1 mmol) of zinc acetate dihydrate and 1.1 g (1.1mmol) of the product obtained in ex. 60 are mixed in 4.0 g of imidazoleand stirred at 160° C. for 7 hours. Then the reaction mixture isextracted with CH₂Cl₂ and the combined extracts are treated using columnchromatography (silica gel, CH₂Cl₂—MeOH as eluent).

Example 64

[0309] 560 mg (1.0 mmol) of the product obtained in ex. 61 are treatedwith 100 mg of terephthaloyl chloride (0.51 mmol) in the presence ofEt₃N (0.5 ml) in 10 ml of CH₂Cl₂ at room temperature for two hours. Theresulting solid is filtered and washed first with MeOH, then CH₂Cl₂, andthereafter with acetone. An insoluble yellow solid is obtained. TABLE 10compounds of formula II example R₉ R₁₀ Yield(%) Colour Mp. (° C.) 60phenyl 3-(hydroxy- 99 Yellow 141.5-142.3 methyl)- phenyl 61 4- 4-amino-76 Orange 202.6-204.4 phenoxy- 2,5-di- phenyl methyl- phenyl 62 phenyl3-(bromo- 60 Yellow 157.4-159.6 methyl)- phenyl

[0310] Similarly the following compounds of formula II are prepared:TABLE 11 compounds of formula II ex. R₉ R₁₀ Yield(%) Colour Mp. (° C.)65 phenyl phenyl 75 Yellow 170.3-173.7 66 phenyl 2,6-diisopropylphenyl94 Pale green- 217.3-222.9 nish-yellow 67 phenyl 4-phenoxyphenyl 86Yellow 186.9-188.7 68 4-phenoxyphenyl 2,6-diisopropylphenyl 90 Yellow202.8-205.2 69 4-diphenylaminophenyl 2,6-diisopropylphenyl 63 Red165.0-167.5 70 4-phenoxyphenyl 2,6-dimethylphenyl 93 Yellow 239.0-240.971 4-phenoxypjhenyl phenyl 93 Yellow 175.6-178.9 72 4-phenoxyphenyl2-chlorophenyl 45 Yellow 184.0-186.4 73 4-phenoxyphenyl 2-methylphenyl95 Yellow 204.4-207.1 74 4-phenoxyphenyl 2,6-dichlorophenyl 10 Yellow189.5-191.8 77 4-phenoxyphenyl 2-amino-4,5-dimethylphenyl 64 Orange97.6-99.8 78 4-phenoxyphenyl 2-phenylphenyl 58 Pale Yellow 170.7-173.879 4-diphenylaminophenyl 2-methylphenyl 75 Reddish- 249.9-252.8 orange80 4-phenoxyphenyl 2-phenoxyphenyl 44 Yellow 194.6-196.2 814-phenoxyphenyl 4-aminocarbonylphenyl 65 Yellowish- 189.1-190.1 orange82 4-methoxy-1-naphthyl 2-phenoxyphenyl 81 Orange 132.0-135.0 834-diphenylaminophenyl 2-phenoxyphenyl 7 Red 140.1-143.3 843-(N-ethyl)-carbazole 2,6-dimethylphenyl 100 Reddish- >250 orange 854-phenylthiophenyl 2,6-dimethylphenyl 71 Orange 178.6-180.4 874-morpholino- 2,6-dimethylphenyl 87 Reddish- >250 phenyl orange 884-phenoxyphenyl 1-pyrenyl 71 Yellow >250 89 2-naphthyl2,6-dimethylphenyl 95 Yellow 189.7-190.7 91 1-pyrenyl 2,6-dimethylphenyl100 Orange >250 92 4-methoxy-1-naphthyl 2,6-dimethylphenyl 100 Orange149.7-151.6

[0311] TABLE 12 compounds of formula IV (R₁₃ = R₁₄ = R₁₆ = R₁₇) exampleR₁₃ R₁₅ Yield(%) Colour Mp. (° C.) 57 phenyl 2,5-di-tert.-butyl- 70greenish-yellow >250 1,4-phenylene 58 phenyl 1,5-naphthylene 84 Paleyellow >250 63 4-phenoxyphenyl perylene derivative 22Reddish-orange >250 of formula

64 4-phenoxyphenyl diamide of formula 54 Yellow >250

[0312] Similarly the following compounds of formula IV are obtained:TABLE 13 compounds of formula IV (R₁₃ = R₁₄ = R₁₆ = R₁₇) example R₁₃ R₁₅Yield(%) Colour Mp. (° C.) 75 4-phenoxyphenyl 2,5-dimethyl-1,4- 21Yellow >250 phenylene 76 4-phenoxyphenyl 4,5-dimethyl-1,2-  8 Yellow166.1-168.7 phenylene 90 4-phenoxyphenyl a biradical of the 57 Yellow220.7-221.3 formula

[0313] Similarly the following compounds of formula III are obtained:TABLE 14 compounds of formula III example R₁₁ R₁₂ R₁₃ Yield(%) ColourMp. (° C.) 86 4-phenoxyphenyl 4-diphenylamino- 2,6-dimethyl- 87 Orange231.1-231.9 phenyl phenyl 93 4-chlorophenyl 4-diphenylamino-2,6-dimethyl- 92 Reddish-orange 115.7-117.1 phenyl phenyl 944-methoxy-1- 4-diphenylamino- 2,6-dimethyl- 90 Red 142.3-144.6 naphthylphenyl phenyl 95 4-methoxy-1- 4-phenylthio- 2,6-dimethyl- 83 Orange 99.5-100.6 naphthyl phenyl phenyl

Example 96

[0314] 7.5 9 (30 mmol) of diphenylmaleic anhydride and 750 mg (15 mmol)of hydrazine hydrate are heated to a temperature of 120° C. ino-dichlorobenzene for 16 hours. After the reaction mixture is allowed tocool to room temperature, 100 ml of hexane are added and the obtainedprecipitate is collected by filtration. After drying, 4.6 g (62%) of apale yellow solid are obtained. Melting point: >250° C.

Example 97

[0315] (a) 20 g (78 mmol) of diphenylmaleic anhydride in acetone (600ml) are irradiated by 400 W high pressure Hg lamp in the presence ofiodine (85 mg, 0.34 mmol) for 21 hours. The resulting pale yellow solidis filtered and washed with acetone. 7.9 g of pale yellow solid9,10-phenanthrenedicaboxylic anhydride are obtained (41%). (b) 500 mg(2.0 mmol) of 9,10-phenanthrenedicaboxylic anhydride are treated with390 mg (2.0 mmol) of 2,6-diisopropylaniline (90%) in 10 ml of aceticacid and heated to reflux for 6 hours. After addition of H₂O, theresulting solid is filtered and washed with H₂O and MeOH. The product ispurified by column chromatography (silica gel, CH₂Cl₂-hexane mixture aseluent). 220 mg of a pale yellow solid are obtained (28%). Meltingpoint: >250° C.

Example 98

[0316] 3.74 g (15.1 mmol) of 9,10-phenanthrenedicaboxylic anhydride(from ex. 97 (a)) are treated with 3.66 g (30.2 mmol) of2,6-dimethylaniline in 30 ml of acetic acid and heated to reflux for 30hours. After addition of H₂O, the resulting solid is filtered and washedwith H₂O and MeOH. The product is purified by column chromatography(silica gel, CH₂Cl₂-hexane mixture as eluent). 3.06 g of a pale yellowsolid are obtained (58%). Melting point: 198.7-199.1° C.

Example 99

[0317] (a) 1.01 g (4.08 mmol) of 9,10-phenanthrenedicaboxylic anhydride(from ex. 97 (a)) are treated with 6.34 g (82.3 mmol) of ammoniumacetate in 12 ml of acetic acid and heated to reflux for 50 hours. Afteraddition of H₂O, the resulting solid is filtered and washed first withH₂O, then MeOH, and thereafter with CH₂Cl₂. The obtained pale yellowsolid is treated with 4.56 g (20.9 mmol) of di-tert.-butyl-dicarbonate(“(BOC)₂O”) in the presence of p-dimethylaminopyridine in DMF for oneday. After addition of H₂O, the resulting solid is filtered and washedwith H₂O and then MeOH. 793 mg of N-BOC-9,10-phenanthrenedicaboximideare obtained after purification using column chromatography (silica gel,CH₂Cl₂-hexane mixture as eluent).

[0318] (b) 403 mg (1.16 mmol) of this N-BOC derivative are treated with10 ml of 50% CH₂Cl₂ solution of trifluoroacetic acid at room temperaturefor 45 min. The reaction mixture is neutralized with 10 ml of ansaturated aqueous NaHCO₃ solution and the resulting solid is filtered.Washing with MeOH and CH₂Cl₂ afforded the pure desired product. 230 mgof a pale yellow solid are obtained (80% from the N-BOC derivative).Melting point: >250° C.

Example 100

[0319] To 30 g (230 mmol) of AlCl₃ in CH₂Cl₂ (75 ml) are added dropwiseto a mixture of 17 g (100 mmol) of 4-phenoxybenzene and 21 g (150 mmol)of ethyl chloroglyoxylate in CH₂Cl₂ (75 ml) at ice-bath temperature overone hour. After completion of addition, the mixture is gradually warmedup to room temperature and stirred overnight. Then, the reaction mixtureis poured onto ice. The aq. solution is acidified to pH 3 with a HCl aq.solution. Then the reaction mixture is extracted with CH₂Cl₂. Thereafterthe extract is dried over anhydrous MgSO₄. The product is furtherpurified by silica gel column chromatography using CH₂Cl₂-hexane mixtureas eluent. 11 g of a white solid are obtained (31% based on4-phenoxybenzene in addition to 4-phenoxyphenyl glyoxylic acid ethylester (37%). 11 g (29 mmol) of the white solid, a diester, arehydrolyzed with 3.7 g (89 mmol) of NaOH (96%) in 70 ml of H₂O and 70 mlof EtOH and heated to reflux for 5 hours. The mixture is acidified to pH3, and then the product, a diacid, is extracted with CH₂Cl₂. 9.2 g of anoil are obtained as a crude product. This product is used for the nextreaction without further purification. 3.2 g of this oil are treatedwith 2.5 g (22 mmol) of tert.-BuOK in MeOH to obtain the correspondingpotassium salt, and then the solvent is removed by evaporation. Afterdrying in an atmosphere under reduced pressure, the obtained solid ismixed with 3.4 g (21 mmol) of p-methoxyphenylacetic acid in 30 ml ofacetic anhydride and heated to reflux for 6 hours. After removal ofacetic anhydride by evaporation in an atmosphere under reduced pressure,the product is purified by silica gel column chromatography usingCH₂Cl₂-hexane mixture as eluent. This product is treated with 2 ml (23mmol) of isopropylamine in toluene-DMF (3:1, 10 ml) for 4 hours. Afterremoval of the solvents under reduced pressure, the product is purifiedby column chromatography (silica gel, CH₂Cl₂-haxane mixture as eluent).69 mg of a yellow solid is obtained (1.0% from the correspondingdiacid). Melting point: 86.0-89.1° C.

Example 101

[0320] (a) 3,6-Diphenoxy-9,10-phenanthrenedicarboxylic anhydride: 4.9 g(11 mmol) of 3,4-di(4-phenoxyphenyl) maleic anhydride (obtained from ex.1d) in acetone (600 ml) are irradiated by 400 W high pressure Hg lamp inthe presence of iodine (43 mg, 0.17 mmol) for 68 hours. After removal ofacetone, the resulting solid is filtered and washed with acetone. Theproduct is purified by column chromatography (silica gel, CH₂Cl₂-hexanemixture as eluent). 1.4 g of a yellow solid are obtained (30%).

[0321] (b) 450 mg (1.0 mmol) of3,6-diphenoxy-9,10-phenanthrenedicarboxylic anhydride are treated with260 mg (2.1 mmol) of 2,6-dimethylaniline in 10 ml of acetic acid andheated to reflux for 7 hours. After addition of H₂O, the resulting solidis filtered and washed with H₂O. The product is purified by columnchromatography (silica gel, CH₂Cl₂-hexane mixture as eluent). 550 mg ofa yellow solid are obtained (99%). Melting Point: 223.7-224.5° C.

Example 102

[0322] (a) 4-bromomethyl phenyl acetic acid A mixture of 50 g (0.33 mol)of 4-methylphenyl acetic acid, 62 g (0.35mol) of N-bromosuccinimide, 200ml of carbon tetrachloride and 0.1 g of 2,2-azobis(isobutyronitrile) areplaced in a 500 ml flask and heated to reflux with stirring for 4 hours.After the reaction mixture is cooled to room temperature, it is pouredinto 500 ml of water. The obtained precipitate is filtered off, and thenwashed with water. After drying under an atmosphere of reduced pressure,55 g of a white powder are obtained (72%).

[0323] (b) Phosphonium salt A mixture of 11.45 g (0.05 mol) of4-bromomethyl phenyl acetic acid, 13.1 g (0.05 mol) of triphenylphosphine and 500 ml of toluene is refluxed for 2 hours. The reactionmixture is cooled down to room temperature, and the thus obtainedprecipitates are collected by filtration and subsequently washed withhot hexane. After drying, 21.86 g of a phosphonium salt are obtained(89%).

[0324] (c) 4-stilbene acetic acid At room temperature, 4.91 g (0.01 mol)of the above obtained phosphonium salt, 1.17 g (0.011 mol) ofbenzaldehyde, 211 mg (0.8 mmol) 18-crown-6 and 1.68 g (0.03 mol) of KOHare added to 40 ml of dichloromethane and stirred for 18 hours. Afterbeing acidified with 1 M HCl, the dichloromethane is separate off andremoved off in atmosphere under reduced pressure. The product ispurified by column chromatography (silica gel, CH₂Cl₂-methanol mixtureas eluent). After drying, 4-stilbene acetic acid is obtainedquantitatively.

[0325] (d) 3.17 9 (10 mmol) of triphenylamino glyoxylic acid is placedin a flask containing 1.3 g (11.6 mmol) of tert.-BuOK and 30 ml ofmethanol. The mixture is heated up to reflux for 1 hour. Then themethanol is removed to give the corresponding triphenylglyoxylic acidpotassium salt quantitatively. To the obtained triphenylglyoxylic acidpotassium salt 2.38 g (10 mmol) of 4-stilbene acetic acid and 30 ml ofacetic anhydride are added and heated up to 130° C. for 2 hours. Afterthe reaction mixture is cooled to room temperature, acetic anhydride isremoved in an atmosphere under reduced pressure and the product ispurified by column chromatography (silica gel, CH₂Cl₂-hexane mixture aseluent). 2.3 g of the corresponding red solid maleic anhydride areobtained (44%).

[0326] (e) A mixture of 2.08 g (4 mmol) of this maleic anhydride, 2.12 g(12 mmol) of 2,6-diisopropylaniline and 25 ml of acetic acid is heatedup to 150° C. for 12 hours. After the acetic acid is removed in anatmosphere under reduced pressure, the product is purified by columnchromatography (silica gel, CH₂Cl₂-hexane mixture as eluent). 2.45 g ofa red solid maleimide of formula XI

[0327] are obtained (90%).

Example 103

[0328] example 102 is repeated except that 2-pyridinecarboxyaldehyde isused at the stage of the Wittig reaction and a red solid compound offormula XII

[0329] is obtained.

Example 104

[0330] example 102 is repeated except that 2-thiophenecarboxyaldehyde isused at the stage of the Wittig reaction and a red solid compound offormula XIII

[0331] is obtained.

Example 105

[0332] example 102 is repeated except that p-tolylaldehyde is used atthe stage of the Wittig reaction and a red solid compound of formula XIV

[0333] is obtained.

Example 106

[0334] example 102 is repeated except that 4-chlorobenzdehyde is used atthe stage of the Wittig reaction and a red solid compound of formula XV

[0335] is obtained.

Example 107

[0336] example 102 is repeated except that 4-phenoxyphenylglyoxylic acidis used for the preparation of maleic anhydride to give a yellowfluorescent solid compound of formula XVI

Example 108

[0337] example 102 is repeated except that 4-cyanobenzaldehyde is usedat the stage of the Wittig reaction and a red solid compound of formulaXVII

[0338] is obtained.

Example 109

[0339] example 102 is repeated except that 4-methoxybenzaldehyde is usedat the stage of the Wittig reaction and a red solid compound of formulaXVIII

[0340] is obtained.

Example 110

[0341] A mixture of 5 g (20 mmol) of diphenylmaleic anhydride and 1.14 g(10 mmol) of 1,4-diaminocyclohexane are heated to reflux in a mixture of150 ml toluene and 50 ml of DMF for eight hours. After removal of thesolvent mixture in an atmosphere under reduced pressure, the obtainedcrude solid is washed twice with each 100 ml of acetone. After drying,2.26 g (39%) of a lemon yellow solid is obtained.

Example 111

[0342] Photostability testing of the compounds in high-impactpolystyrene (HIPS)

[0343] 1. Preparation of Samples for the Photostability Testing:

[0344] 1.1 Formulation comprising of the following components isprepared: HIPS (FINA 825 from FINA Oil and Chemical Co.; 99.9 wt-% meltflow index is 8.0 on ASTM D-1238) compound:  0.1 wt-%

[0345] 1.2 Dry tumbling is carried out for the above formulation for 15min.

[0346] 1.3 HIPS plates are prepared with an injection-molding machine at220° C. The dwell time is 3 min.

[0347] 1.4 The plates are exposed to a Xenon-lamp using Fade-O-meter(Model WEL-15X-HC-B.EC, Suga Co. Itd.) under the following condition:Xe-lamp power: 0.35 W/m² at 340 nm Black panel temperature: 63° C.Humidity (relative): 50% Mode: no-rain

[0348] 1.5 Photostability after 100-hour exposure is evaluated in termsof photoluminescence intensity and color change (ΔE_(ab) and bluescale).

[0349] 2 Results:

[0350] The results are summarized in the table below.

[0351] Plates prepared from maleimides obtained in ex. 39 and ex. 79 arefound to retain strong photoluminescence intensities, even after100-hour weathering test. The above compounds display color change(ΔE_(ab)), corresponding to the results of Gray Scale evaluation (themaximum scale is “5”). TABLE 15 Results of photostability tests BeforeAfter 100-hour exposure plates ob- exposure Photolu- tained withPhotolumin- mines- compounds escence cence Gray of example: Colorintensity intensity ΔE_(ab) scale 39 greenish yellow 928.6 721.1 5.21 524 yellow 876.2 450.1 11.90 73 yellow 668.0 484.9 5.18 79 reddish orange504.7 483.7 0.50 5 46 orange 548.4 525.7 1.55 44 yellowish orange 485.9364.8 2.43 27 orange 432.4 391.3 3.59 82 orange 372.2 345.8 2.22 36orange 879.2 657.1 11.43 37 yellow 973.4 684.7 7.53 38 yellow 154.9126.0 1.92 45 yellow 940.3 685.0 6.53 47 orange 682.0 561.3 4.88 84reddish orange 718.6 673.0 1.70 85 orange 981.1 803.3 4.10

Example 112

[0352] Photostability testing of the compounds in nitrocellulose(“NC”)-ink formulation

[0353] 1. Preparation of the Ink Formulation:

[0354] 1.1 Formulation comprising of the following components isprepared: glass beads ( 2.0-2.8 mm): 66.66 wt.-%  NC clear: 31.75wt.-%  compound: 1.59 wt.-% formulation of NC clear is as follows:nitrocellulose: 15.0 wt.-% di-2-ethyl hexyl adipate:  3.0 wt.-% ethylcellosolve: 10.0 wt.-% methyl ethyl ketone: 25.0 wt.-% ethyl alcohol:47.0 wt.-%

[0355] 1.2 The above formulation is applied to a dispersor (LAU GmbH,model BA-S 20 K) for two hours to achieve a homogeneous dispersion ofthe pigment.

[0356] 1.3 The dispersion obtained is applied on a transparent polyestersubstarte film using a blade to give ca. 100 μm thick of the paintedlayer.

[0357] 1.4 The film is exposed to a Xe-lamp using a Fade-Ometer (ModelWEL-15-X-HC-B.EC, Suga Co.Ltd.) under the following condition: Xe-lamppower: 0.35 W/m² at 340 nm black panel temperature: 63° C. humidity(releative): 50% mode: no-rain

[0358] 1.5 Photostability after 100-hour exposure is evaluated in termsof photoluminescence intensity and color change (ΔE_(ab) and bluescale).

[0359] 2 Results

[0360] The results are summarized in the Table below

[0361] The following compounds show photoluminescence intensitiesstronger than the commercial products, i.e. Radiant, even after 100-hourweathering test: ex. 39, 41, 25, 24, 70, 72, 73, 74, 80, and 45. TABLE16 Results of photostability tests in NC-ink formulation Before After100-hour exposure plates ob- exposure Photolu- tained with Photolumi-mines- compounds nescence cence Blue of example: Color intensityintensity ΔE_(ab) scale 39 greenish yellow 3203 2609 8.21  5-6 41 yellow2358 1413 5.39  4-5 25 yellow 2441 1673 2.57  5-6 24 yellow 1973 96811.18  5-6 70 yellow 2748 2287 4.05 >6 72 yellow 2914 1860 5.18  5-6 73yellow 2681 2122 4.67 5 74 yellow 3041 2147 4.46 6 80 yellow 1663 16320.73 6 45 yellow 1673 1109 5.47 6 Radiant Y. 2093 115 28.98 <3 RadiantR. 1640 116 25.44 <3 Radiant O. 1267 32 25.07 <3

Example 113

[0362] Photostability testing of the compounds in linseed oil inkformulation

[0363] 1. Preparation of the Ink Formulation:

[0364] 1.1 Formulation comprising of the following components isprepared: linseed oil: 75.0 wt.-% compound: 25.0 wt.-%

[0365] 1.2 The above formulation is applied to an Automatic HooverMuller (from Toyo Seiki Co.) for three minutes to achieve a homogeneousdispersion of the pigment.

[0366] 1.3 The dispersion obtained is applied on a white paper substrateusing a blade to give a 100 μm thick painted layer.

[0367] 1.4 The film is exposed to a Xe-lamp using a Fade-Ometer (ModelWEL-15-X-HC-B.EC, Suga Co.Ltd.) under the following condition: Xe-lamppower: 0.35 W/m² at 340 nm black panel temperature: 63° C. humidity(relative): 50% mode: no-rain

[0368] 1.5 Photostability after 100-hour exposure is evaluated in termsof photoluminescence intensity and color change (ΔE_(ab) and bluescale).

[0369] 2. Results

[0370] The results are summarized in the Table below. The followingcompounds show photoluminescence intensities stronger than thecommercial products, i.e. Radiant, even after 100-hour weathering test:compounds from ex. 39, 41, 25, 70, and 80. In addition, these compoundsdisplay a color change ΔE_(ab) superior to the state of the artcompounds. TABLE 17 Results of photostability tests in linseed oil inkformulation Before After 100-hour exposure plates ob- exposure Photolu-tained with Photolumin- mines- compounds escence cence Blue of example:Color intensity intensity ΔE_(ab) scale 39 greenish yellow 4124 39712.35 6 41 yellow 3209 3511 3.16 6 25 yellow 3421 2680 2.44 6 70 yellow3624 3181 3.48 6 80 yellow 2225 1889 1.59 6 Radiant Y. 5217 1616 56.79<3 Radiant R. 3227 2159 40.46 <3 Radiant O. 4386 1237 45.90 <3

Example 114

[0371] Photostability testing of the compounds in PMMA

[0372] 1. Preparation of Samples for the Photostability Testing:

[0373] 1.1 Formulation comprising of the following components isprepared:

[0374] PMMA (Sumiplex LG from Sumitomo Chemical Co.; melt flow index is10 g/10 min on JIS-K7210): 99.9 wt.-% compound:  0.1 wt.-%

[0375] 1.2 Dry tumbling is carried out for the above formulation for 15minutes.

[0376] 1.3 PMMA plates are prepared with an injection-molding machine at220° C. The dwell time is three minutes.

[0377] 1.4 The plate is exposed to a Xe-lamp using a Fade-Ometer (ModelWEL-15-X-HC-B.EC, Suga Co. Ltd.) under the following condition: Xe-lamppower: 0.35 W/m² at 340 nm black panel temperature: 63° C. humidity(relative): 50% mode: no-rain

[0378] 1.5 Photostability after 100-hour exposure is evaluated in termsof photoluminescence intensity and color change (ΔE_(ab) and bluescale).

[0379] 2 Results

[0380] The results are summarized in the Table below. Compounds of ex.39, 70, 80, 79, and 46 are found to retain strong photoluminescenceintensity, even after 100-hour weathering test. The above mentionedcompounds exhibit a small color change (ΔE_(ab)), corresponding to theresults of a Gray Scale evaluation (maximum scale=“5”). The comparativeexamples from Radiant are evaluated only using a Gray Scale, indicatingthat the results are inferior to the inventive compounds. TABLE 18Results of photostability tests in PMMA Before After 100-hour exposureplates ob- exposure Photolu- tained with Photolumin- mines- compoundsescence cence Gray of example: Color intensity intensity ΔE_(ab) scale39 greenish yellow 752 607 6.75 4-5 70 yellow 698 523 7.66 4-5 80 yellow400 286 6.14 4-5 79 reddish orange 331 319 0.53 5 46 orange 393 371 0.735 Radiant Y. 3-4 Radiant R. 2 Radiant O. 1-2

Example 115

[0381] On an ITO glass substrate (made by Geomatech Co. Ltd., ITO filmthickness 200 nm, sheet resistance 10 Ω/cm²), a diamine represented bythe following formula

[0382] is deposited as a hole transporting substance by vacuumevaporation under a vacuum of 6.65×10⁻⁴ Pa (5.0×10⁻⁶ Torr) and at adepositing rate of 0.05 nm/sec to a membrane thickness of 50 nm.

[0383] Then, on the hole transporting layer thus prepared, the productobtained in ex. 37 is deposited under a depositing condition of6.65×10⁻⁴ Pa (5.0×10⁻⁶ Torr) and 0.05 nm/sec to a membrane thickness of50 nm to form a light-emitting layer.

[0384] Then, this light-emitting layer, firstly lithium is doped withthe above compound at a rate of 0.015 nm/s to form a 1 nm-thick layerand subsequently aluminum as cathode are deposited on it to a filmthickness of 200 nm.

[0385] By using the ITO side as the anode and the magnesium side as thecathode, a bias of 20 V is applied to the above element. A luminescenceshowing a luminance of 248 cd/m² (using Luminometer LS-110 manufacturedby Minolta Co, Ltd) is obtained as the average value of the fiveelements.

Examples 116-125

[0386] Examples 115 is repeated, except the following light-emittingcompounds are employed. The results are summarized in Table 19 belowtogether with the results of Example 115. TABLE 19 Light-emittingcompound Luminance Example obtained from example: λ_(EL) (nm) (cd/m²)115 37 556 248 116 22 514 60 117 38 552 126 118 25 553 14 119 69 628 152120 70 551 150 121 79 633 81 122 80 554 120 123 46 618 233 124 55 554 61125 102 641 350

Example 126

[0387] Void Detection A waterborne primer based on acrylic latex isprepared according to the following formulation: Composition wt.-%  1)Demineralized water 3.10  2) Methylcarbitol^(a)) 5.00   3) Orotan165^(b)) 0.82  4) Triton CF 10^(c)) 0.29  5) Drew Plus TS 4380^(d)) 0.28 6) Acrysol RM 8^(e)) 0.60  7) Bayferrox 130 M^(f)) 5.72  8)Millicarb^(g)) 17.40  9) fluorescent agent 10) Butyldiglykol 3.67 11)Maincote HG-54^(h)) (41.5% supply form) 58.70 12) Texanol ^(i)) 1.50 13)Di-butylphthalate^(k)) 1.50 14) Sodium nitrite^(l))(13.8% in dem. water)0.80 15) Drew T 4310^(m)) 0.32 16) ammonia(25%) 0.30 Total 100.0

[0388] wherein:

[0389] a) Methylcarbitol: di-ethylene-glykolmonomethylether (from UnionCarbide); b) Orotan 165: dispersing agent (Rohm and Haas Company); c)Triton CF 10: non-ionic wetting agent (Rohm and Haas Comp.); d) DrewPlus TS 4380: defoamer (Drew Chem. Corp.) e) Acrysol RM 8: non-ionicthickener (Rohm and Haas Comp.); f) Bayferrox 130 M: red iron oxidepigment (Bayer AG); g) Millicarb: calcium carbonate (Omya); h) MaincoteHG-54: acrylic dispersion (Rohm and Haas Comp.); i) Texanol. coalescent(Eastman Chem. Prod., Inc.); k) Di-butylphthalate: plastisizer (EastmanChem. Prod., Inc.); I) sodium nitrite: flash rust inhibitor (Fluka); m)Drew T 4310: non-ionic defoamer (Drew Chem. Corp.)

[0390] As fluorescent agents the following maleimides (component 9)obtained from examples 35, 98, 28, 22, 33, 31, 96, as well as a mixtureof 1,2,3,4-tetraphenyl-benzo[4,5]imidazo[2,1-a]isoindol-11-one-7 and -8(obtained according to example 1 of WO 98/33862 are used. The components1 to 8 or 1 to 9 respectively are dispersed at 3000 rpm to a particlesize of <15 μm using a high-speed disperser. The compounds I or Ia ofthe present invention are thereby incorporated in a range chosen from0.1 to 1% by weight, based on the total solids of the formulationcontaining no fluorescent agent (solids content=47% by weight).According to this, a concentration of 1% b.w. translates to 0.47 g per100 g paint. The formulation is completed under reduced speed (100 rpm)by adding the components 10 to 16 in the given order. Prior toapplication the pH of the formulation is adjusted to pH 8-8.5 using aammonium hydroxide solution (25%).

[0391] The formulations are sprayed onto aluminum panels at a dry filmthickness in the range of from 50 to 55 μm. Once the formulations arecured the coatings are inspected under an UV-lamp. Defects or voids as aresult of misapplication or artificially applied defects can be easilydetected, as the compounds of the present invention show intensefluorescence only at the voids. No fluorescence is observed in theabsence of the fluorescent agents.

Example 127

[0392] A solvent based white pigmented 2 pack epoxy primer is preparedaccording to the following formulation: Composition parts by wt. 1)Araldit GZ 7071^(a)) (75% in xylene) 24.2 2) Aerosil R 972^(b)) 0.5 3)Thixatrol ST^(c)) 0.2 4) Kronos RN 56^(d)) 25.0 5) Bayferrox 318M^(e))0.1 6) Micr. Talk AT Extra^(f)) 15.8 7) Blanc Fixe^(g)) 14.2 8)Cyclohexanone 8.3 9) Xylene 11.7 10) n-Butanol 10.0 11) fluorescentagent Subtotal 110.0 12) Hardener HY 815^(h)) (50% in xylene) 18.2 Total128.2

[0393] wherein

[0394] a) Araldit GZ 7071: epoxy resin (Ciba Specialty Chemicals, Inc.);b) Aerosil R 972: synthetic silica, thickener (Degussa AG); c) ThixatrolST: anti-settling agent, thixotropic agent (Kronos Titan GmbH); d)Kronos RN 56: titanium dioxide (Kronos Titan GmbH); e) Bayferrox 318 M:iron oxide black (Bayer AG); f) Talc AT Extra (Norwegian); g) BlancFixe: barium sulphate (Sachtleben); h) Hardener HY 815: polyamido amine(Ciba Specialty Chemicals, Inc.)

[0395] As fluorescent agents the following maleimides (component 11)obtained from examples 35, 98, 28, 22, 33, 31, 96, as well as a mixtureof 1,2,3,4-tetraphenyl-benzo[4,5]imidazo[2,1-a]isoindol-11-one-7 and -8(obtained according to example 1 of WO 98/33862) are used.

[0396] The components 1 to 10 or 1 to 11 respectively are dispersed on aball mill or equivalent to a particle size <15 μm. The compounds of thepresent invention are thereby incorporated in a range of from 0.1 to 1%b.w. The amounts are based on the total solids of the formulationcontaining no fluorescent agent (solids=64.8% b.w.). According to thisan amount of 1% b.w. corresponds to 0.64 g per 128.2 g paint. Prior toapplication the hardener (component 12) is added. For spray applicationthe viscosity is adjusted using xylene as a solvent.

[0397] The formulations are sprayed onto aluminium panels at a dry filmthickness of 70 μm. Once the formulations are cured the coatings areinspected under a UV-lamp. Defects or voids as a result ofmisapplication or artificially applied defects can be easily detected,as the compounds of the present invention show intense fluorescence atthe voids. No fluorescence is observed in the absence of the fluorescentagents. cl Example 128

[0398] A 2 pack epoxy primer according to example 127 is preparedthereby replacing component 4 (Kronos RN 56) by iron oxide red(Bayferrox 318 M). The resulting red/brownish formulation is made andevaluated as described in example 127.

Example 129

[0399] The inventive maleimides according to formula I are incorporatedin a concentration of 0.5% to 1% (based on the total solids of theformulation containing no fluorescent agent; solids content=19%) into acommercial automotive cathodic electrocoat. During electrodeposition thebath temperature is kept at 28° C. whilst stirring. The electrocoat isdeposited onto steel panels at 250 Volts for 2 minutes. Afterapplication the panels are rinsed with demineralized water andsubsequently baked at 180° C. for 25 minutes. The resulting filmthickness is 25 μm. Once the formulations are cured, the coatings areinspected under a UV-lamp. Defects or voids as a result ofmisapplication or artificially applied defects can be easily detected,as the compounds of the present invention show intense fluorescence atthe voids. No fluorescence is observed in the absence of the fluorescentagents.

Example 130

[0400] Example 115 is repeated replacing the light-emitting material andthe cathode with the film co-deposited usingtris-(8-hydroxyquinolinato)aluminum(III) (manufactured by Wako PureChemicals Industries, Ltd.) and the compound of formula XI (ca. 4.0wt %)and the cathode co-deposited using magnesium and silver (Mg:Ag, 20:1),respectively. The co-deposition is done under a depositing condition of6.665×10⁻⁴ Pa (5.0×10⁻⁶ Torr) and 320 pm/s (3.2 Å/s) for the aluminumcomplex, 13 pm/s (0.13 Å/s) for the compound of formula XI, 200 pm/s(2.0 Å/s) for magnesium and 10 pm/s (0.1 Å/s) for silver. Forcomparison, the device employing the compound of the complex forlight-emitting substance is prepared using the cathode of Mg:Ag (20:1).

[0401] The device the light-emitting layer of which comprises of solelythe aluminum complex indicates green EL emission. The emission maximumis at 520 nm in wavelength. The device the light-emitting layer of whichcomprises of the complex and the compound of formula XI exhibits ELemission whose maximum wavelength is at 620 nm, i.e. an orange redemission which is different from that of the single component deviceabove. This suggests that the emission is induced via resonance energytransfer from the aluminum complex to the compound invented.

[0402] The above results demonstrate that the invented compounds areuseful for energy acceptor of Host-Guest type of light-emittingmaterials.

Example 131

[0403] (a) 5.5 g (0.02 mol) of 4-trans-stilbene glyoxylic acid is placedin a flask containing 2.46 g (22 mmol) of tert.-BuOK and 30 ml ofmethanol. The mixture is heated up to reflux for 30 min. Then themethanol is removed to give the corresponding 4-trans-stilbene glyoxylicacid potassium salt. To the obtained potassium salt 4.76 g (20 mmol) of4-transstilbene acetic acid and 30 ml of acetic anhydride are added andheated up to 130° C. for 2 hours. After cooling to room temperature,acetic anhydride is removed from the mixture and the product is purifiedby column chromatography (silica gel, CH₂Cl₂/hexane). 6.5 g (62%) of thecorresponding maleic anhydride obtained.

[0404] A mixture of 4.55 g (10 mmol) of the thus obtained maleicanhydride, 7.1 g (30 mmol) of 2,6-diisopropylaniline and 50 ml of aceticacid is heated up to 130° C. form eight hours. After the acetic acid isremoved under an atmosphere or reduced pressure, the product is purifiedby column chromatography (silica gel, CH₂Cl₂/hexane). 5.03 g (82%) of anorange-red maleimide of the formula XIX are obtained

Example 132

[0405] Example 131 is repeated except that cyclohexylamine is usedinstead of 2,6-diisopropylaniline. An orange solid (72%) of the formulaXX is obtained

Example 133

[0406] Example 102 is repeated except that cyclohexylamine is usedinstead of 2,6-diisopropylaniline. A red solid (68%) of the formula XXIis obtained

Example 134

[0407] Example 102 is repeated except that isopropylamine is usedinstead of 2,6-diisopropylaniline. A red solid (73%) of the formula XXIIis obtained

Example 135

[0408] Example 102 is repeated except that o-toluidine is used insteadof 2,6-diisopropylaniline. A red solid (76%) of the formula XIII isobtained

Example 136

[0409] Example 102 is repeated except that ethyleneamine is used insteadof 2,6-diisopropylaniline. A red solid (54%) of the formula XXIV isobtained

Example 137

[0410] Example 102 is repeated except that 1,4-diaminocyclohexane isused instead of 2,6-diisopropylaniline. A red solid (58%) of the formulaXXV is obtained

Example 138

[0411] 5.35 g (20 mmol) of 9-ethylcarbazole-3-glyoxylic acid is placedin a flask containing 2.46 g (22 mmol) of tert.-BuOK and 25 ml ofmethanol. The mixture is heated up to reflux for 30 min. Then themethanol is removed to give the corresponding 4-trans-stilbene glyoxylicacid potassium salt. To the obtained potassium salt 4.76 g (20 mmol) of4-trans-stilbene acetic acid and 30 ml of acetic anhydride are added andheated up to 130° C. for 2 hours. After cooling to room temperature,acetic anhydride is removed from the mixture and the product is purifiedby column chromatography (silica gel, CH₂Cl₂/hexane). 7.1 g (73%) of thecorresponding maleic anhydride are obtained.

[0412] (b) A mixture of 4.83 g (10 mmol) of the thus obtained maleicanhydride, 7.1 g (30 mmol) of 2,6-diisopropylaniline and 50 ml of aceticacid is heated up to 130° C. form eight hours. After the acetic acid isremoved under an atmosphere of reduced pressure, the product is purifiedby column chromatography (silica gel, CH₂Cl₂/hexane). 5.01 g (78%) of anorange-red maleimide of the formula XXVI are obtained

Example 139

[0413] (a) To 24.6 g (0.18 mol) of AlCl₃ in 200 ml of CH₂Cl₂ a mixtureof 30 g (0.12 mol) of 9-phenyl carbazole and 17.75 g (0.13 mol) of ethylchloroglyoxylate in 100 ml of CH₂Cl₂ is added dropwise at ice-bathtemperature over 1 h. After completion of addition, the mixture isgradually allowed to room temperature and stirred over night. Then, thereaction mixture is poured onto ice. The aqueous solution is acidifiedto pH 3 with aq. HCl, and the product is extracted with CH₂Cl₂afterwards. The extract is dried over anhydrous MgSO₄. The desiredproduct is purified by Silica gel column chromatography usingCH₂Cl₂-hexane mixture as eluent. 24.5 g of ethyl3-(9-phenylcarbazole)-glyoxylate are obtained (58%).

[0414] (b) 24.5 g (0.07 mol) of ethyl 3-(9-phenylcarbazole)glyoxylateare treated with 3.6 g (0.09 mol) of NaOH in 75 ml of H₂O and 75 ml ofethanol under reflux for 2 h The mixture is acidified to pH 3 with aq.HCl, and then extracted with CH₂Cl₂. After drying, 17.0 9 of3-(9-phenylcarbazole)glyoxylic acid are obtained as a crude product(74%). This product is used for the next reaction step without furtherpurification.

[0415] (c) 3.15 g (0.01 mol) of 3-(9-phenylcarbazole)glyoxylic acid areplaced in a flask containing 1.23 g (0.011 mol) of tert-BuOK and 30 mlof methanol The mixture is heated up to reflux for 30 min. Then themethanol is removed to give 3-(9-phenylcarbazole)glyoxylic acidpotassium salt. To the obtained potassium salt, 2.37 g (0.01 mol) of4-trans-stilbene acetic acid and 30 ml of acetic anhydride are added andheat up to 130° C. for 4 hours. After the reaction mixture is allowed tocool to room temperature, acetic anhydride is removed and the product ispurified by column chromatography (silica gel, CH₂Cl₂hexane mixture) 1.1g (22%) of the corresponding maleic anhydride are obtained.

[0416] (d) 1.1 g (2.1 mmol) of this maleic anhydride, 0.63 g (6.3 mmol)of cyclohexylamine, 10 ml of N,N-dimethylformamide and 30 ml of tolueneare heated up to 130° C. for 6 hours. After the used solvents areremoved under an atmosphere of reduced pressure, the product is purifiedby column chromatography (silica gel, CH₂Cl₂-hexane mixture). 0.91 g(72%) of an orange-red maleimide XXVII are obtained

Example 140

[0417] Example 115 is repeated, except the following light emittingcompounds are employed. The results are summarized in the Table 20.TABLE 20 Light-Emitting Material EL Emission Peak EL Intensity Example(Example) wavelength (nm) (cd/m²) 140 131 589 230 141 132 582 243 142133 637 400 143 134 659 82 145 136 656 94 146 137 655 164 147 138 618430 148 139 610 320

Example 149

[0418] Example 115 is repeated for EL device preparation using as lightemitting material compound XIX (ex. 131) as an energy donor andLumogen®Red 300 (BASF) as an energy acceptor. Table 21 below shows theresults.

Example 150-151

[0419] Example 149 is repeated, except the following light energy donorsare employed (see Table 21). The results are summarized in Table 21.TABLE 21 Guest/ Lumogen ® EL Emission Host Red 300 Peak materialconcentration wavelength EL Intensity Example (example) [wt.-%] [nm][cd/m²] 149 107 1 609 522 150 131 2 612 478 151 132 1.8 614 548

1. Maleimides of the formula I

wherein R₁ and R₂ independently from each other stand for

wherein Q₁ stands for hydrogen, halogen, phenyl, —E—C₁-C₈alkyl,—E-phenyl, wherein phenyl can be substituted up to three times withC₁-C₈alkyl, halogen, C₁-C₈alkoxy, diphenylamino, —CH═CH-Q₂, wherein Q₂stands for phenyl, pyridyl, or thiophenyl, which can be substituted upto three times with C₁-C₈alkyl, halogen, C₁-C₈alkoxy, —CN, wherein Estands for oxygen or sulfur, and wherein R₂₁ stands for C₁-C₈alkyl,phenyl, which can be substituted up to three times with C₁-C₄alkyl,C₁-C₄alkoxy, or dimethylamino, and R₂₂ and R₂₃ independently from eachother stand for hydrogen, R₂₁, C₁-C₈alkoxy, or dimethylamino, or —NR₄R₅,wherein R₄ and R₅, independently from each other stand for hydrogen,phenyl, or C₁-C₈alkyl-carbonyl, or —NR₄R₅ stands for a five- orsix-membered ring system, and R₃ stands for allyl,

wherein Q₃ stands for hydrogen, halogen, C₁-C₈alkoxy, orC₁-C₈alkyl-amido, unsubstituted or substituted C₁-C₈alkyl, unsubstitutedor up to three times with halogen, —NH₂, —OH, or C₁-C₈alkyl substitutedphenyl, and Z stands for a di- or trivalent radical selected from thegroup consisting of substituted or unsubstituted cyclohexylene,preferably 1,4-cyclohexylene, triazin-2,4,6-triyl, C₁-C₆alkylene,1,5-naphthylene,

wherein Z₁, Z₂ and Z₃, independently from each other stand forcyclohexylene or up to three times with C₁-C₄alkyl substituted orunsubstituted phenylene, preferably unsubstituted or substituted1,4-phenylene, and wherein R₆ and R₇, independently from each other,stand for

n stands for 1, 2 or 3, and m stands for 1 or 2, with the proviso, thatR₁ and R₂ not simultaneously stand for phenyl.
 2. Process for thepreparation of maleimides of the formula I according to claim 1 byreacting a maleic anhydride with an amine, which comprises using asmaleic anhydride the diarylmaleic anhydride of the formula V

wherein R₁₈ and R₁₉, independently from each other stand for R₁ or R₂ asdefined in claim 1, and as amine the amine H₂N—R₃ or the diamineH₂N—Z—NH₂, wherein R₃ and Z are defined in claim
 1. 3. A process for thepreparation of maleimides I as set forth in claim 1, which comprisesreacting in a first step the diarylmaleic anhydride V as set forth inclaim 2 with ammonium acetate, then—in a second step—reacting the thusobtained intermediate Vb

with a base, and in a third step reacting the obtained anion with ahalogen compound X—R₃ or X—Z—X, wherein R₃ and Z are defined as setforth in claim 1, and X stands for halogen.
 4. Method of using amaleimide I or a maleimide of formula Ia

as UV fluorescent material for void detection and for the preparation ofscintillators films, luminescent solar energy collectors, organicelectroluminescent devices, printing inks, non-impact printing inks,electrophotographic toners, color filters, and colored high molecularorganic material.
 5. Method of inspecting the surface of a bodycomprising the steps of: (a) covering a surface with a compositioncomprising a compound exhibiting edge fluorescence, (b) inspecting thethus covered surface with ultraviolet light for visible light, suchbeing indicative of faults in the surface.
 6. Method according to claim5, wherein the compound exhibiting edge fluorescence is a maleimide I ora maleimide of formula Ia

wherein R₃ is defined as in claim 1, preferably1,1′-(1,2-ethanediyl)bis[3,4-diphenyl]-1H-pyrrole-2,5-dione.
 7. Anarticle of manufacture comprising: a body having a surface to becovered; a layer of coating material on the surface of the body,fluorescing means blended with said coating material for emittingidentifiable visible light in response to exposure to ultraviolet light.8. The article according to claim 7, wherein the fluorescing means is amaleimide I or a maleimide of formula Ia

wherein R₃ is defined as in claim 1, preferably1,1′-(1,2-ethanediyl)bis[3,4-diphenyl]-1H-pyrrole-2,5-dione. 9.Electroluminescent devices comprising fluorescent maleimides of theformula I according to claim 1 or Ia

wherein R₃ is defined as in claim 1.